Bulletin of the American Physical Society
APS March Meeting 2016
Volume 61, Number 2
Monday–Friday, March 14–18, 2016; Baltimore, Maryland
Session K6: RuthenatesFocus
|
Hide Abstracts |
Sponsoring Units: GMAG DMP Chair: Songxue Chi, Oak Ridge National Laboratory Room: 302 |
Wednesday, March 16, 2016 8:00AM - 8:36AM |
K6.00001: \textbf{Tuning quantum properties in bilayer ruthenates } Invited Speaker: Xianglin Ke The mutual coupling among spin, charge, lattice and orbital degrees of freedom in transition-metal oxide materials often leads to the competition of various types of energetic states. This makes such materials dramatically susceptible to external parameters, giving rise to novel physical properties and rich phase diagrams. In this talk, I shall use a bilayer ruthenate, Ca$_{3}$Ru$_{2}$O$_{7}$, as an example to discuss the emergent phenomena achieved by systematically tuning materials magnetic and electronic properties via chemical doping, magnetic field, and pressure. I shall show that this system provides a rare opportunity to investigate the interplay between correlated metal and Mott insulator. This work was done in collaboration with M. Zhu, T. Tao, S. D. Mahanti, Z. Q. Mao, J. Peng, T. Hong, W. Tian, H. Cao, C. R. dela Cruz, D. Singh, and K. Prokes. [Preview Abstract] |
Wednesday, March 16, 2016 8:36AM - 8:48AM |
K6.00002: \textbf{Metamagnetism and Nonlinear Susceptibilities in the Bilayer Ruthenate Sr}$_{\mathbf{3}}$\textbf{Ru}$_{\mathbf{2}}$\textbf{O}$_{\mathbf{7}}$ D Phelan, B. Shivaram, A Vecchione, Rosalba Fittipaldi We report measurements of the third and fifth order nonlinear susceptibilities in the correlated oxide metamagnet, Sr$_{3}$Ru$_{2}$O$_{7}$ for both orientations of the magnetic field, H parallel to the c-axis and in the basal plane. In both geometries we observe peaks in the temperature dependence of the higher order susceptibilities. The position in temperature where the peak in the fifth order susceptibility occurs is at half the temperature where a peak in the third order susceptibility is seen. The latter in turn is at half the temperature where the peak in the linear susceptibility is known to occur. This simple scaling is common to both orientations of the magnetic field. These results will be discussed in the context of similar work with heavy fermion metamagnets$^{1}$. [Preview Abstract] |
Wednesday, March 16, 2016 8:48AM - 9:00AM |
K6.00003: \textbf{Structure-magnetism correlation induced by Mn substitution in bilayered perovskite Sr}$_{\mathbf{3}}$\textbf{(Ru}$_{\mathbf{1-x}}$\textbf{Mn}$_{\mathbf{x}}$\textbf{)}$_{\mathbf{2}}$\textbf{O}$_{\mathbf{7}}$\textbf{ } Qiang Zhang, Feng Ye, Songxue Chi, Dalgis Mesa, Wei Tian, Rongying Jin, Ward Plummer, Jiandi Zhang Elastic neutron scattering technique was employed to investigate the effect of Mn substitution on the structure, magnetism and their correlation in Sr$_{3}$(Ru$_{1-x}$Mn$_{x})_{2}$O$_{7\, }$(x$=$6{\%}, 12{\%} and 16{\%}) crystals. While parent compound Sr$_{3}$Ru$_{2}$O$_{7\, }$is paramagnetic, a small amount of Mn substitution induces an E-type antiferromagnetic order. With the increase of Mn substitution from 6 {\%} to 16{\%}, the ordered moment at Ru/Mn site increases significantly with an enhanced $T_{N}$ from 20 K for x$=$6 {\%} to 80 K for x$=$ 16{\%}, and the in-plane magnetic correlation lengths increase to achieve the maximum for x$=$ 16{\%} as indicated by the resolution-limited linewidth of the $H $scans through \textbf{Q}$_{\mathbf{AFM}}=$(0.5, 0, 0). Accompanied by the enhancement of $T_{N}$, the (Ru/Mn)O$_{6}$ octahedron rotation is found to be suppressed simultaneously, suggesting a correlation between (Ru/Mn)O$_{6}$ octahedron rotation and magnetism due to Mn substitution. Our findings indicate that Mn substitution on Ru in Sr$_{3}$Ru$_{2}$O$_{7}$ has a significant effect on the microscopic structure and magnetism as well as the correlations between them. [Preview Abstract] |
Wednesday, March 16, 2016 9:00AM - 9:12AM |
K6.00004: Magnetic phase separation in double layer ruthenates Ca$_3$(Ru$_{1-x}$Ti$_x$)$_2$O$_7$ Jin Peng, Jinyu Liu, Jin Hu, zhiqiang Mao, Xiaoshan Wu Ti doping of a small concentration in the double-layered ruthenate Ca$_3$(Ru$_{1-x}$Ti$_x$)$_2$O$_7$ was previously found to induce an unusual magnetic phase transition from a metallic antiferromagnetic state formed from anti-parallel stacking of ferromagnetic bilayers (AFM-b) to a nearest-neighbor antiferromagnetic state (G-AFM) with Mott insulating properties; the critical Ti concentration for the transition is near $x$ = 0.03. In this article, we conducted systematic studies on this magnetic transition near the critical composition through detailed magnetization measurements. We found that no intermediate magnetic phases exist between AFM-b and G-AFM states; this is contrasted with manganites where a similar magnetic phase transition takes place through the presence of several intermediate magnetic phases. The AFM-b-to-G-AFM transition in Ca$_3$(Ru$_{1-x}$Ti$_x$)$_2$O$_7$ happens through a phase separation process; the AFM-b and G-AFM phases coexist in the 2-5% Ti range. Another distinct characteristic of this magnetic transition is that it is triggered by low concentration impurity doping (< 5%), whereas similar magnetic transitions in manganites are tuned by 50-70% chemical substitutions. We have discussed the possible origin of such an unusual magnetic transition and com [Preview Abstract] |
Wednesday, March 16, 2016 9:12AM - 9:48AM |
K6.00005: Field-controlled spin-density-wave order and quantum critically in Sr3Ru2O7 Invited Speaker: Stephen Hayden The quasi-2D metamagnetic perovskite metal Sr$_3$Ru$_2$O$_7$ has been an enigma for the last decade. The application of a large magnetic field of ~8T parallel to the c-axis creates a new phase at low temperatures. This phase shows ``electronic nematic'' properties in that strong anisotropy its resistivity can be created by tilting the field away from the c-axis. In addition, measurement of transport and thermodynamic properties suggest that the phase is at the centre of a quantum critical region. Here we use neutron scattering to show that the magnetic field actually induces spin-density-wave magnetic order in the proximity of a metamagnetic critical endpoint. In fact, Sr$_3$Ru$_2$O$_7$ can be tuned through two magnetically-ordered SDW states which exist over relatively small ranges in field (< 0.4 T). Their origin is probably due to the electronic fine structure near the Fermi energy. The magnetic field direction is shown to control the SDW domain populations which naturally explains the strong resistivity anisotropy or "electronic nematic" behaviour observed in this material. We find that Sr$_3$Ru$_2$O$_7$ is also unique in that its the quantum critical region is controlled by overdamped incommensurate low-energy spin fluctuations with a diverging relaxation time. The low-energy electronic properties reflect the presence of these fluctuations and, in particular, the field-dependent low-temperature specific heat is proportional to the spin relaxation rate. [Based on C. Lester, S. Ramos, R. S. Perry at el. Natural Materials 14, 373 (2015).] [Preview Abstract] |
Wednesday, March 16, 2016 9:48AM - 10:00AM |
K6.00006: Magnetic-field-induced first-order phase transitions in Ca$_{\mathrm{3}}$(Ru$_{\mathrm{1-x}}$Fe$_{\mathrm{x}})_{\mathrm{2}}$O$_{\mathrm{7}}$ with unusual irreversible behaviors Mengze Zhu, Jin Peng, Tao Zou, Tao Hong, Karel Prokes, S. D. Mahanti, Zhiqiang Mao, Xianglin Ke Neutron diffraction measurements reveal a magnetic-field-induced incommensurate-commensurate magnetic structure transition in a bilayer ruthenate Ca$_{\mathrm{3}}$(Ru$_{\mathrm{1-x}}$Fe$_{\mathrm{x}})_{\mathrm{2}}$O$_{\mathrm{7\thinspace }}(x =$ 0.05). The transition is of first-order in nature, and exhibits intriguing irreversible behaviors at low temperature, i.e. the zero-field incommensurate state before and after field sweeping showing very distinct magnetic ordering wave vectors. The difference in the wavelength of magnetic ordering is strongly temperature-dependent, and disappears gradually as temperature raises. This unusual irreversibility in magnetic ordering vector is rarely observed, and in disagreement with phase coexistence phenomena that is commonly seen in other irreversible first-order phase transitions. Nevertheless, our results demonstrate that thermal fluctuations also play an essential role in this unusual behavior. [Preview Abstract] |
Wednesday, March 16, 2016 10:00AM - 10:12AM |
K6.00007: Unconventional Magnetic Domains in Triple-layered Sr$_{4}$Ru$_{3}$O$_{10}$ Kai Du, Seong Joon Lim, Jae Wook Kim, Gang Cao, Sang Wook Cheong A plethora of fascinating phenomena including p-wave superconductivity in Sr$_{2}$RuO$_{4}$ (n=1) and hybrid improper ferroelectricity in Ca$_{3}$Ru$_{2}$O$_{7}$ (n=2) have been observed in Ruddlesden-Popper ruthenates (Ca, Sr)$_{n+1}$Ru$_{n}$O$_{3n+1}$. The triple-layered Sr$_{4}$Ru$_{3}$O$_{10}$ (n=3) is believed to have an intriguing complex magnetic state, compared with its neighboring bi-layered meta-magnetic Sr$_{3}$Ru$_{2}$O$_{7}$(n=2) and ferromagnetic SrRuO$_{3}$ (n=$\infty$). The phase competition nature associated with this complexity is considered to be responsible for its novel properties such as coupled anisotropic magnetism and transport, low frequency quantum oscillations and sharp magneto-resistivity steps, which are still not well understood yet. To better understand its microscopic mechanism, we studied the magnetic domain structure on Sr$_{4}$Ru$_{3}$O$_{10}$ using low-temperature magnetic force microscopy. The observed unique domain structures in Sr$_{4}$Ru$_{3}$O$_{10}$ may shed lights on its microscopic phase competition nature and lead to a deeper understanding on its relations with other layered ruthenates. [Preview Abstract] |
Wednesday, March 16, 2016 10:12AM - 10:24AM |
K6.00008: Dynamical mean field study of ferromagnetism and correlation strength in cubic barium ruthenate: results and comparison to strontium and calcium ruthenate Qiang Han, Hung Dang, Andrew Millis We present density functional plus dynamical mean field studies of cubic BaRuO$_3$ using interaction parameters previously found to be appropriate for the related materials CaRuO$_3$ and SrRuO$_3$. The calculated trends in material properties across this family of compounds are in good agreement with experiment and the results provide insights into the origin of magnetism and the role of the van Hove singularity in the physics of Hunds metals. [Preview Abstract] |
Wednesday, March 16, 2016 10:24AM - 10:36AM |
K6.00009: Ferromagnetic cluster glass state induced by non-magnetic ions in a paramagnetic host Takafumi D. Yamamoto, Ryuji Okazaki, Hiroki Taniguchi, Ichiro Terasaki A paramagnetic metal CaRuO$_3$ has been known to show unique impurity effects, where a magnetic ordering is induced by a partial substitution of transition metal ions for Ru. Since this phenomenon occurs regardless of the magnetism of the substituted ions, it must reflect a magnetic instability of this ruthenate. Understanding such physical properties is one of intriguing issues in condensed matter physics. \par In this talk, we report an unconventional magnetic state induced by substituting non-magnetic Sc$^{3+}$ ions. We find that the static magnetic susceptibilities of all Sc-substituted samples show ferromagnetic-like features below 40 K, while the Curie-Weiss temperature dramatically changes with increasing $x$. This inconsistency is a sign of \textit{non-uniform magnetic system}. We propose a phenomenological model and show that the static magnetic properties can be described as a volume average of a paramagnetic component originated from Ru$^{4+}$ ions and a ferromagnetic one driven by Sc substitution [T.~D.~Yamamoto \textit{et al}., JPSJ \textbf{84}, 014708 (2015).]. Furthermore our dynamic magnetic measurements reveal a ferromagnetic cluster glass state embedded in the paramagnetic and metallic host of CaRuO$_3$. [Preview Abstract] |
Wednesday, March 16, 2016 10:36AM - 10:48AM |
K6.00010: Suppression of ferromagnetism and observation of quantum well states in epitaxial thin films of the cubic ruthenate BaRuO$_{3}$. Bulat Burganov, Hanjong Paik, Kyle Shen, Darrell Schlom The pseudocubic perovskite ruthenates ARuO$_{3}$, where A is alkaline earth metal, are correlated materials where Hund's coupling drives correlations and leads to a low coherence scale, large renormalization, and formation of local moments. The ferromagnetic BaRuO$_{3}$ has an ideal cubic structure and a larger bandwidth, compared to its GdFeO$_{3}$-distorted counterparts, CaRuO$_{3}$ and SrRuO$_{3}$. In stark contrast to SrRuO$_{3}$, which is a Fermi liquid below T$_{C}$, BaRuO$_{3}$ exhibits critical fluctuations near T$_{C}$ that are enhanced under hydrostatic pressure, which suppresses the Fermi liquid coherence scale and T$_{C}$ and drives a crossover into non-FL regime. Here we use ARPES to characterize the momentum-resolved electronic structure of strained ultrathin BaRuO$_{3}$ films grown in situ by molecular beam epitaxy. The films on STO (001) are metallic down to 2 u.c. thickness and manifest clearly defined subbands of well-defined quasiparticles which arise due to quantum confinement effects. We observe that the bands are moderately renormalized compared to bare GGA bands and discover that the ferromagnetism can be suppressed in the atomically thin limit. We discuss our results on BaRuO$_{3}$ in the context of our recent ARPES studies of the other perovskite ruthenates, SrRuO$_{3}$ and CaRuO$_{3}$. [Preview Abstract] |
Wednesday, March 16, 2016 10:48AM - 11:00AM |
K6.00011: Antiferromagnetism in Bulk Rutile RuO$_2$ T. Berlijn, P. C. Snijders, P. R. C. Kent, T. A. Maier, H.-D. Zhou, H.-B. Cao, O. Delaire, Y. Wang, M. Koehler, H. H. Weitering While bulk rutile RuO$_2$ has long been considered to be a Pauli paramagnet, we conclude it to host antiferromagnetism based on our combined theoretical and experimental study. This constitutes an important finding given the large amount of applications of RuO$_2$ in the electrochemical and electronics industry. Furthermore the high onset temperature of the antiferromagnetism around 1000K together with the high electrical conductivity makes RuO$_2$ unique among the ruthenates and among oxide materials in general. [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. |
© 2024 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
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700