Pressure dependence of exchange interactions and Neel temperature in transition metal oxides

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