Pressure Dependence Of The Magnetic Ordering Temperature (T-C) For The Na2mn[Mn(Cn)(6)] Noncubic Prussian Blue Analogue

The pressure dependence of the magnetic properties of rhombohedral Na2Mn[Mn(CN)(6)] up to 10 kbar has been studied. The magnetic ordering temperature, T-c, for Na2Mn[Mn(CN)(6)] reversibly increases with increasing applied hydrostatic pressure, P, by 9.0 K (15.2%) to 68 K at 10 kbar with an average rate of increase, dT(c)/dP, of 0.86 K/kbar. The magnetization at 50 kOe and remanent magnetization, M-r(H), remain constant with an average value of 13,100 +/- 200 and 8500 +/- 200 emuOe/mol. The coercive field H-cr increases by 12% from 13,400 to 15,000 Oe. The increase and rate of increase of T-c for rhombohedral Na2Mn[Mn(CN)(6)] are reduced with respect to monoclinic A(2)Mn[Mn(CN)(6)] (A = K and Rb), but they are still greater than those of cubic Cs2Mn[Mn(CN)(6)]. This is attributed to the compression of the MnNC framework bonding without decreasing angle Mn-II-N C, maintaining the unit cell in accord with cubic A = Cs at lower applied pressures, and not due to reduction in angle Mn-II-N C, which correlates with increasing T-c that is reported for A = K and Rb as well as Cs at higher applied pressures.