Magnetic frustration in the spinel compounds Ge Co_2 O_4 and Ge Ni_2 O_4

Abstract

In both spinel compounds GeCo${}_2$O${}_4$ and GeNi${}_2$O${}_4$ which order antiferromagnetically (at $T_N=23.5K$ and $T_{N_1}=12.13K$, $T_{N_2}=11.46K$) with different Curie Weiss temperatures ($T_{CW}$=80.5 K and -15 K), the usual magnetic frustration criterion $f=|T_{CW}|/T_N>>1$ is not fulfilled. Using neutron powder diffraction and magnetization measurements up to 55 T, both compounds are found with a close magnetic ground state at low temperature and a similar magnetic behavior (but with a different energy scale), even though spin anisotropy and first neighbor exchange interactions are quite different. This magnetic behavior can be understood when considering the main four magnetic exchange interactions. Frustration mechanisms are then enlightened.

submitted to Phys.Rev.B (2006)

Cited by in corpus (9)

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• Structural distortion below the Néel temperature in spinel GeCo${}_2$O${}_4$
• Jahn-Teller Inactivity and Magnetic Frustration in GeCo${}_2$O${}_4$ Probed by Ultrasound Velocity Measurements
• Elastic Instabilities within Antiferromagnetically Ordered Phase in the Orbitally-Frustrated Spinel GeCo${}_2$O${}_4$
• Unusual UUDD magnetic chain structure of the spin-1/2 tetragonally distorted spinel GeCu2O4
• Lattice dynamics and magnetic exchange interactions in GeCo2O4, a spinel with S = 1/2 pyrochlore lattice
• Field driven magnetostructural transitions in GeCo${}_2$O${}_4$
• Hedgehog lattice and field-induced chirality in breathing-pyrochlore Heisenberg antiferromagnets
• Magnetic Field Induced Phase Transition in Spinel GeNi2O4