Enhanced pressure dependence of magnetic exchange in A2+[V2]O4 spinels approaching the itinerant electron limit.
We report a systematic enhancement of the pressure dependence of T(N) in A(2+)[V(2)]O(4) spinels as the V-V separation approaches the critical separation for a transition to itinerant-electron behavior. An intermediate phase between localized and itinerant-electron behavior is identified in Zn[V(2)]O(4) and Mg[V(2)]O(4) exhibiting mobile holes as large polarons. Partial electronic delocalization, cooperative ordering of V-V pairs in Zn[V(2)]O(4) below T(s) approximately T(N) and dT(N)/dP<0, signals that lattice instabilities associated with the electronic crossover are a universal phenomenon.
Blanco-Canosa
S
S
Departamento de Química-Física, Universidad de Santiago de Compostela, 15782-Santiago de Compostela, Spain.
Rivadulla
F
F
Pardo
V
V
Baldomir
D
D
Zhou
J-S
JS
García-Hernández
M
M
López-Quintela
M A
MA
Rivas
J
J
Goodenough
J B
JB