Singh Ripandeep, Hansen T, Ritter C, Sharma Neetika, Shahi P, Chatterjee S, Das A
Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
J Phys Condens Matter. 2017 Aug 31;29(34):345802. doi: 10.1088/1361-648X/aa7c3e. Epub 2017 Jun 28.
The influence of external pressure (P ⩽ 5 GPa) on both the structural and magnetic ordering in MnVO has been investigated using neutron diffraction technique. The volume and the V-V distance decrease with pressure while the c/a ratio increases, suggesting a lowering of the distortion with pressure. Under ambient conditions this compound exhibits a structural transition (T ) from tetragonal to cubic at ~53 K and a magnetic transition (T ) at ~56 K. It is found that with an increase in pressure to 5 GPa, T increases (from 56 K to 80 K), dT /dP > 0, while T decreases (from 53 K to 37 K). The non collinear magnetic structure in the tetragonal phase at 5 GPa and 10 K remains the same as at ambient pressure. However, the Mn and V sublattice, now exhibits distinct transition temperatures, [Formula: see text] ~ 80 K, and [Formula: see text] ~ 60 K. The transition to the cubic phase at T is accompanied by a collinear alignment of the Mn and V spins and a reduction in the Mn moment. The region in which the structure remains in the cubic phase with collinear magnetic structure increases with pressure from ~3 K at ambient pressure to ~43 K at 5 GPa pressure.
利用中子衍射技术研究了外部压力（P⩽5 GPa）对MnVO结构和磁有序的影响。体积和V-V距离随压力减小，而c/a比增加，表明压力使畸变降低。在环境条件下，该化合物在约53 K时表现出从四方相到立方相的结构转变（T），在约56 K时表现出磁转变（T）。研究发现，随着压力增加到5 GPa，T增加（从56 K增加到80 K），dT/dP > 0，而T降低（从53 K降低到37 K）。5 GPa和10 K时四方相的非共线磁结构与常压下相同。然而，Mn和V亚晶格现在表现出不同的转变温度，[公式：见正文]约80 K，[公式：见正文]约60 K。在T时向立方相的转变伴随着Mn和V自旋的共线排列以及Mn磁矩的减小。结构保持具有共线磁结构的立方相的区域随压力从常压下的约3 K增加到5 GPa压力下的约43 K。
