### Session Q30: Focus Session: High Pressure III

11:15 AM–2:15 PM, Wednesday, March 17, 2010
Room: D139

Chair: Ken Esler, University of Illinois at Urbana-Champaign

Abstract ID: BAPS.2010.MAR.Q30.7

### Abstract: Q30.00007 : Pressure dependence of exchange interactions and Neel temperature in transition metal oxides

12:27 PM–12:39 PM

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#### Authors:

Julius Ojwang
(Carnegie Institution of Washington)

Ronald Cohen
(Carnegie Institution of Washington)

Luke Shulenburger
(Carnegie Institution of Washington)

Xiangang Wan
(Nanjing University)

Serjey Savrasov
( UC Davis Physics Department)

We perform first-principles linear response computations within LDA+U and GGA+U to systematically investigate the pressure dependence of magnetic exchange interactions for archetypal transition metal oxides (TMOs): MnO, FeO, CoO, and NiO. We obtain the Neel temperatures (T$_N$) using Monte Carlo simulations. We find that the magnitude of the next nearest neighbor coupling constant, J2, which dominates T$_N$, increases with increasing pressure, while the nearest neighbor, J1, behaves differently for the four TMOs. The variation of T$_N$ with pressure is influenced by interplay between the nearest and next nearest neighbor exchange coupling constants. Our results are found to be in agreement in general with most experiments [1-3]. \\[4pt] [1] Massey et al. Phys. Rev. B 42:8776, 1990\\[0pt] [2] Sidorov Appl. Phys. Lett. 72:2174, 1998\\[0pt] [3] Badro et al. Phys. Rev. Lett. 83:4101, 1999\\[0pt] [4] Pasternak et al. Phys. Rev. Lett. 79:5046, 1997

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.Q30.7