Bulletin of the American Physical Society
APS March Meeting 2015
Volume 60, Number 1
Monday–Friday, March 2–6, 2015; San Antonio, Texas
Session T31: Focus Session: Ruthenates and Other Oxides |
Hide Abstracts |
Sponsoring Units: GMAG DMP Chair: Dennis Meier, ETH Zuerich Room: 207A |
Thursday, March 5, 2015 11:15AM - 11:27AM |
T31.00001: Field-induced antiferromagnetic order in Sr$_3$Ru$_2$O$_7$ Christopher Lester, Stephen Hayden, Silvia Ramos, Robin Perry, Thomas Croft, Robert Bewley, Tatiana Guidi, Pascal Manuel, Dmitry Khalyavin Many novel electronic ground states form in close proximity to quantum critical points, that is, the point where a continuous phase transition occurs at zero temperature. By suppressing the metamagnetic transition in Sr$_3$Ru$_2$O$_7$ to low temperatures via the application of a magnetic field, the system is driven into a 'nematic' phase. This phase occurs at temperatures below approximately 1~K and at fields $\mu_0H_c\approx8$~T. The phase is often described as nematic since transport properties display pronounced anisotropic tendencies which are not present in the underlying crystal lattice. Using elastic neutron scattering we have found evidence for two adjacent magnetically ordered phases near $\mu_0H_c$ in this material. The period of the order in both phases is incommensurate with the underlying lattice and most likely determined by the electronic band structure. The presence of static antiferromagnetic order provides a very natural explanation for the anisotropic transport properties that have been observed in this system. Our observation of field-induced antiferromagnetic order in a clean metal provides valuable insights into the physics of novel phase formation near quantum critical points. [Preview Abstract] |
Thursday, March 5, 2015 11:27AM - 11:39AM |
T31.00002: Possible spin-momentum locking and band-dependent coherence in Sr3Ru2O7 revealed by angle-dependent magneto thermoelectric measurements Chenyi Shen, Hui Xing, Xinxin Cai, David Fobes, Mingliang Tian, Zhiqiang Mao, Zhuan Xu, Ying Liu The bilayer member of the Roddlesden-Popper(R-P) series, Sr3Ru2O7, with its complex phenomena such as a magnetic field orientation dependent metamagnetic transition and the possible existence of a nematic phase, has attracted much attention. Both INS and NMR studies suggested that the metamagnetic transition is band dependent and some bands of Sr3Ru2O7 are heavily renormalized according to the ARPES experiment. However, the underlying electronic and magnetic properties of these bands are yet to be clarified. We explored band dependent electronic and magnetic properties in Sr3Ru2O7 by using angle-dependent magnetoresistance and magneto thermoelectric measurements on crystals cut along two specific crystalline directions and a magnetic field rotating in the ab plane. We found evidence supporting the presence of spin-momentum locking and the emergence of a coherent state with unconventional magnetism phase formed in a two-dimensional band in Sr3Ru2O7. [Preview Abstract] |
Thursday, March 5, 2015 11:39AM - 11:51AM |
T31.00003: Soft magnetic excitations and quantum critically in Sr$_3$Ru$_2$O$_7$ Stephen Hayden, C. Lester, R. Ramos, R. Perry, T. Croft, R. Bewley, T. Guidi, E. Forgan The application of a magnetic field of approximately $B_c=8~T$ induces quantum critical behavior in Sr$_3$Ru$_2$O$_7$. Near $B_c$, the resistivity shows an anomalous power law temperature dependence and the linear specific heat becomes large. In addition, new ordered phases with strong nematic tendencies appear below $1~K$ near $ B_c$. These phases have recently been identified as spin density wave order. Here we report an inelastic neutron scattering study of the low-energy magnetic excitations. We find a dramatic field-induced softening of the collective magnetic excitations in the region surrounding $B_c$. This suggests that the quantum critically observed in Sr$_3$Ru$_2$O$_7$ is magnetic in origin. The presence of additional magnetic excitations can also explain the increase in entropy and specific heat present near $B_c$. [Preview Abstract] |
Thursday, March 5, 2015 11:51AM - 12:03PM |
T31.00004: Double metamagnetic transition in Sr$_{4}$Ru$_{3}$O$_{10}$ investigated by low temperature magnetization measurements Dagmar Franziska Weickert, Leonardo Civale, Marcelo Jaime, Boris Maiorov, Roman Movshovich, R. Fittipaldi, V. Granata, A. Vecchione, Teng Tan, Myron Salamon We report a study of the magnetization of the n$=$3 member of the Sr$_{n+1}$Ru$_{n}$O$_{3n+1}$ Ruddlesden-Popper series down to $^{3}$He temperatures. Sr$_{4}$Ru$_{3}$O$_{10}$ exhibits~ferromagnetism below 105 K with magnetic moments aligned along the crystallographic $c$-direction in the tetragonal crystal structure. Metamagnetism is observed at about 2 T below 50 K when a magnetic field is applied in the \textit{ab}- plane. A recent study on high quality samples revealed that the metamagnetism has a substructure [1]. We extend the studies to very low temperatures and found i) a clear double peak in dM/dH, ii) that the metamagnetism is accompanied by a reduction of the magnetic moment and iii) no further splitting of the metamagnetic anomalies to the lowest temperatures of 0.46 K. Furthermore, the measurements indicate a shift of both metamagnetic signatures to higher fields by rotating from $H$//\textit{ab} to $H//c$. We will discuss the phase diagram and possible ordered states. \\[4pt] [1] E. Carleschi et \textit{al}. PRB \textbf{90}, 205120 (2014). [Preview Abstract] |
Thursday, March 5, 2015 12:03PM - 12:15PM |
T31.00005: Optical Response of Sr$_{2}$RuO$_{4}$ Reveals Universal Fermi-liquid Scaling and Quasiparticles Beyond Landau Theory Damien Stricker, Jernej Mravlje, Christophe Berthod, Rosalba Fittipaldi, Antonio Vecchione, Antoine Georges, Dirk van der Marel We report optical measurements demonstrating that the low-energy relaxation rate (1/$\tau )$ of the conduction electrons in Sr$_{2}$RuO$_{4}$ obeys scaling relations for its frequency ($\omega )$ and temperature (T) dependence in accordance with Fermi-liquid theory. In the thermal relaxation regime, 1/$\tau \propto $ ($\hbar \omega )^{2} + $ (p$\pi $k$_{\mathrm{B}}$T)$^{2}$ with p $=$ 2, and $\omega $/T scaling applies. Many-body electronic structure calculations using dynamical mean-field theory confirm the low-energy Fermi-liquid scaling, and provide quantitative understanding of the deviations from Fermi-liquid behavior at higher energy and temperature. In this regime, evidence for electron-like ``resilient'' quasiparticle excitations with a scattering rate deviating from Landau's Fermi-liquid form is presented. [Preview Abstract] |
Thursday, March 5, 2015 12:15PM - 12:27PM |
T31.00006: Commensurate-incommensurate magnetic phase transition in the Fe-doped ruthenate bilayer Ca$_{3}$Ru$_{2}$O$_{7}$ Xianglin Ke, M. Zhu, W. Tian, T. Hong, J. Peng, Z.Q. Mao Neutron diffraction studies have revealed an uncommon commensurate-incommensurate magnetic phase transition with decreasing temperature in the ($\sim$ 5{\%}) Fe-doped bilayer ruthenate Ca$_{3}$(Ru,Fe)$_{2}$O$_{7}$. An incommensurate phase formed of a cycloidal spiral spin structure coexists with a commensurate one below the phase transition at 42 K and persists down to the lowest temperature, accompanied by higher-order magnetic satellite peaks which indicate the formation of a magnetic soliton lattice. We ascribe these findings to the competing magnetic interactions in Ca$_{3}$Ru$_{2}$O$_{7}$. This study demonstrates an effective approach to tune novel magnetic and electronic properties of this complex system via 3d magnetic transition-metal substitution. \\[4pt] [1] X. Ke et al, Phys. Rev. B. \textbf{89}. 220407 (R) (2014). [Preview Abstract] |
Thursday, March 5, 2015 12:27PM - 12:39PM |
T31.00007: ARPES and spin ARPES measurements of nonmagnetic centrosymmetric crystal LaBiOS$_{2}$ Justin Waugh, Xiaoqing Zhou, Haoxiang Li, Thomas Nummy, Stephen Parham, Qihang Liu, Xiuwen Zhang, Jasminka Terzic, Xiangde Zhu, Gang Cao, Alex Zunger, Daniel Dessau Spin polarized bands are traditionally expected to exist only under global bulk symmetry breaking. LaBiOS$_{2}$ has a centrosymmetric structure thus expected to have no spin polarization. However, it is predicted to have local inversion-asymmetric structure, leading to spin polarization localized on the individual BiS$_{2}$ sublayers. This spin polarization theoretically presents itself in energetically doubly degenerate bands that are spatially separated on different BiS$_{2}$ layers. We measured ARPES and spin ARPES on the inversion-symmetric bulk crystal LaBiOS$_{2}$ in search of such a hidden spin polarization. Our measurements show band structure to have qualitative agreement with DFT calculations. We additionally observe spin polarization in the valence band and will discuss its spin orientation in this talk. This work is supported by NSF DMREF project 1334170. [Preview Abstract] |
Thursday, March 5, 2015 12:39PM - 12:51PM |
T31.00008: Anisotrophic Magnetocaloric Effect in Single Crystalline CoSb$_2$O$_6$ Aaron B. Christian, John J. Neumeier, Yi-Kuo Yu The quasi one-dimensional spin chains of CoSb$_2$O$_6$ are oriented along [110] at $z=0$ and [1$\bar{1}$0] at $z=1/2$. Application of magnetic field $H$ parallel to [110] is therefore parallel to one set of chains and perpendicular to the other. $H>2$ tesla, applied parallel to [110], lowers the N\'eel temperature ($T_N = 13.4$ K) for one set of chains, leaving the other set unaffected. This gives rise to two peaks in the heat capacity $C_P$, which are separated by 3.8 K when $H=8$ tesla. Integrating $C_P(T,H)/T$ with respect to temperature yields a change in entropy $\Delta S_T$, from which the change in \textit{magnetic} entropy $\Delta S_m(\Delta H)=\Delta S_T(H_2)-\Delta S_T(H_1)$, is determined. Near 12 K we find that $\Delta S_m$(8 T) = 2.97 J/kg K for measurements with $H \parallel [110]$ or [$1\bar{1}$0] and $\Delta S_m$(8 T) = 0.44 J/kg K for $H \parallel [001]$. This anisotropy implies that rotation of the sample in \textit{constant} magnetic field could induce a change in sample temperature. [Preview Abstract] |
Thursday, March 5, 2015 12:51PM - 1:03PM |
T31.00009: Hall effect of triplons in a dimerized quantum magnet Judit Romhanyi, Karlo Penc, Ramachandran Ganesh SrCu$_2$(BO$_3$)$_2$ is the archetypal quantum magnet with a gapped dimer-singlet ground state and triplon excitations. It serves as a realization of the Shastry Sutherland model, up to small anisotropies arising from Dzyaloshinskii-Moriya (DM) interactions. We demonstrate that the DM couplings give rise to topological character in the triplon band structure. The triplons form a new kind of a Dirac cone with three bands touching at a single point, a spin-1 generalization of graphene. An applied magnetic field opens band gaps and as a result topological bands with Chern numbers $\pm 2$ develop. Thus SrCu$_2$(BO$_3$)$_2$ is a magnetic analogue of the integer quantum Hall effect and supports topologically protected edge modes. At a critical value of the magnetic field set by the strength of DM interactions, the three triplon bands touch again in a spin-1 Dirac cone, and lose their topological character. We predict thermal Hall signature in the topological regime. [Preview Abstract] |
Thursday, March 5, 2015 1:03PM - 1:15PM |
T31.00010: Spin induced ferroelectric-like structural transition in a metal Yanfeng Guo, Hai Feng, Princep Andrew, Pascal Manuel, Kazunari Yamaura, Boothroyd Andrew LiOsO$_{3}$ represents a previously only known example of ``ferroelectric metal,'' a concept presented by Anderson and Blount in 1965, with the properties being promoted by electron lattice coupling involving Li$^{+}$ ions displacement in the crystal structure [Y. Shi et al., Nat. Mater. 12, 1024(2013)]. We report that in Pb$_{2}$CoOsO$_{6}$, a new ordered double-perovskite with a centrosymmetric monoclinic space group of $P$2$_{1}$/n, a ferroelectric-like structural transition occurs at $\sim$ 38 K in the metallic state, i.e. a continuous second order transition to a noncentrosymmetric structure (space group: P1) associated by appearance of a nominal unique polar axis along the $c$-axis. The phase transition is coincident with a magnetic transition at the same temperature which corresponds to a long-range antiferromagnetic order. The magnetic structure analysis and theoretical calculations prove that the antiferromagnetic ordering is the driven force for the structural transition in Pb$_{2}$CoOsO$_{6}$ and it represents the first double-perovskite ``ferroelectric metal'' involving a magnetic ordering. [Preview Abstract] |
Thursday, March 5, 2015 1:15PM - 1:27PM |
T31.00011: Anisotropic Magnetocaloric Effect in Single Crystalline NiTa$_2$O$_6$ Aaron T. Schye, Sueli H. Masunaga, Aaron B. Christian, John J. Neumeier, Yi-Kuo Yu Magnetic susceptibility and heat capacity measurements were made on the low-dimensional antiferromagnet NiTa$_2$O$_6$. The antiferromagnetic structure most consistent with our measurements is the two sub-lattice model proposed by Law et al.\footnote{Law et al., \textit{Phys. Rev. B.} \textbf{89}, 014423 (2014).} in which magnetic moments in the z = 0 plane are aligned parallel to [110] and those in the z = 1/2 plane are aligned parallel to [1$\bar{1}$0]. Applying a magnetic field along [110] causes the peak in the heat capacity to split into two with one remaining at $T_N$ and the other shifting to lower temperatures as the field is increased with a maximum $\Delta T$ $\sim$ 3 K at 8 T. This splitting indicates that each sub-lattice orders at different N\'eel temperatures. Calculation of the magnetic entropy change associated with an increase in magnetic field($\Delta S_m(T, \Delta H$)) reveals $\Delta S_m(T, \Delta H$) $\sim$ 0.7 J/kg K for $H \parallel$ [110] and $\Delta S_m(T, \Delta H$) $\sim$ 0 J/kg K for $H \parallel$ [001] if $\Delta H$ = 8 T. This anisotropy in the magnetocaloric effect suggests that rotating the sample in constant magnetic field will result in a change in sample temperature. [Preview Abstract] |
Thursday, March 5, 2015 1:27PM - 1:39PM |
T31.00012: Transport properties of novel molybdenum bronze oxide materials Joseph Hagmann, Son Le, Lynn Schneemeyer, Patti Olsen, Theo Siegrist, Curt Richter, David Seiler Reduced ternary molybdenum oxides, or bronzes, offer an attractive materials platform to study a wide variety of remarkable physical phenomena, including charge density waves [1] and superconductivity [2], in a system with highly varied structural chemistry. Interesting electronic behaviors in these materials arise from the strong hybridization of the 4d states of high-valent Mo with O p orbitals (conditions amenable to itinerancy) and reduced dimensionality arising from ordered O vacancies. This study aims to demonstrate the transport phenomena in a series of novel molybdenum bronze materials, including the new electrochemically-grown molybdenum bronzes, K3Li3Mo15O47, and the rare earth molybdenum bronze, HoMo16O44, and relate these behaviors to their experimentally-characterized structures. Dependence of the transport behavior on numerous experimental parameters, including temperature, magnetic field, drive voltage and drive current, and gate voltage, is presented to fully reveal charge carrier transport in these materials. \\[4pt] [1] Raub, C. J.; Broadsto.S; Matthias, B. T.; Jensen, M. A.; Sweedler, A. R. Physical Review Letters 1964, 13, 746.\\[0pt] [2] Canadell, E.; Whangbo, M. H. In Physics and Chemistry of Low-Dimensional Inorganic Conductors; Schlenker, C., Dumas, J., Greenblatt, M., van Smaalen, S., Eds.; Plenum Press: New York, 1996, p 271. [Preview Abstract] |
Thursday, March 5, 2015 1:39PM - 1:51PM |
T31.00013: Properties of the low dimensional Sr$_{2}$Cu(W$_{1-x}$Mo$_{x}$)O$_{6}$ spin system Omar Chmaissem, Maxim Avdeev, Sergey Danilkin, Sami Vasala, Hisao Yamauchi, Maarit Karppinen Low-dimensional spin systems have gained much attention in solid state physics. Such systems could have a ground state with no long-range magnetic order and an energy gap in the spin excitation spectrum, offering the possibility of a quantum spin-liquid phase. Quantum fluctuations causing the spin-liquid state are particularly strong in systems with reduced dimensionality and a low spin value; and magnetic frustration can further enhance the fluctuations. Among various low-dimensional spin systems, the S = 1/2 Heisenberg frustrated square lattice model is especially interesting due to its relevance to high-T$_{C}$ superconducting cuprates, whose undoped parent materials are S = 1/2 square-lattice antiferromagnets. Sr$_{2}$CuWO$_{6}$ and Sr$_{2}$CuMoO$_{6}$ have been found to be quasi-two-dimensional S = 1/2 magnetic systems with a square lattice of Cu-ions. These compounds show low-dimensional magnetic properties, with no clear indication of long-range order in magnetic susceptibility. I will discuss the materials properties and the observation of long range magnetism by neutron diffraction and other techniques. [Preview Abstract] |
Thursday, March 5, 2015 1:51PM - 2:03PM |
T31.00014: NMR studies of the internal electric field in a single crystal of the quasi-one-dimensional conductor Li$_{0.9}$Mo$_{6}$O$_{17}$ Guoqing Wu, Bing Wu The quasi-one-dimensional (Q1D) conductor Li$_{0.9}$Mo$_{6}$O$_{17}$ is of considerable interest because it has a highly conducting phase with properties likely associated with a Luttinger liquid, a poorly understood ``metal-insulator'' crossover at temperature $T_{\mathrm{MI}}$ = 24 K, and a 3D superconducting phase that may involve triplet Cooper pairs at $T_{c}$ = 2.2 K, while the mechanism for many of its properties has been a long mystery and it presents tremendous experimental challenges. We report the $^{7}$Li-NMR measurements of the internal electric field with an externally applied magnetic field $B_{0}$ = 9 - 12 T, and we also show our theoretically calculated result of the electric field based on the structure of the crystal lattice. We find that the $^{7}$Li-NQR frequency ($\nu_{Q}$) has a value of $\sim$ 45 kHz and the electric field gradient (EFG) at the Li site due to the charges of the surrounding Mo conduction electrons has an axial symmetry with the principle axis ($p_{z}$) to be along the lattice $a$-axis. There is no temperature or field dependence for the value of $\nu_{Q}$ or EFG, indicating that the ``metal-insulator'' crossover has a magnetic origin, rather than the charge density wave (CDW) as one of the possible mechanisms previously thought in literature. [Preview Abstract] |
Thursday, March 5, 2015 2:03PM - 2:15PM |
T31.00015: ARPES and NMTO of Li$_{0.9}$Mo$_{6}$O$_{17}$: Implications for Unusually Robust Quasi-One Dimensional Behavior J.W. Allen, L.M. Dudy, J.D. Denlinger, J. He, M. Greenblatt, M.W. Haverkort, O.K. Andersen, Y. Nohara Li$_{0.9}$Mo$_{6}$O$_{17}$ displays theoretically interesting [1] metallic quasi-one dimensional (1D) behavior that is unusually robust [2] against 3D crossover before superconductivity at $\approx $ 1.9K, and has large anomalous Luttinger liquid density-of states exponent $\alpha \approx $ 0.6. We present very high resolution, low temperature (T $\approx $ 6K-26K) angle resolved photoemission spectroscopy (ARPES) data analyzed with non-linear muffin tin orbital (NMTO) Wannier function band theory. We confirm a previous conclusion [3] that the LDA agrees unusually well with ARPES, implying small Hubbard U, and find in ARPES the dispersion and Fermi surface warping and splitting expected for predicted small but long range inter-chain hoppings (t$_{\mathrm{\bot }}\approx $ 10-15 meV). These various findings imply the likely importance of long range Coulomb interactions for the large $\alpha $ value [4] and reaffirm the great puzzle [2] of quasi-1D behavior well below the 3D crossover T implied by t$_{\mathrm{\bot}}$.\\[4pt] [1] P. Chudzinski, T. Jarlborg and T. Giamarchi, Phys. Rev. B \textbf{86}, 075147 (2012).\\[0pt] [2] L. Dudy \textit{et al}, J. Phys. Condens. Matter \textbf{25}, 014007 (2013).\\[0pt] [3] M. Nuss and M. Aichhorn, Phys. Rev. B \textbf{89}, 045125 (2014).\\[0pt] [4] P. Kopietz, V. Meden and K. Sch\"{o}nhammer, Phys. Rev. Lett. \textbf{74}, 2997 (1995). [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2020 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
1 Research Road, Ridge, NY 11961-2701
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700