Crystal structures of spin-Jahn-Teller ordered MgCr_2O_4 and ZnCr_2O_4

Abstract

Magnetic ordering in the geometrically frustrated magnetic oxide spinels MgCr_2O_4 and ZnCr_2O_4 is accompanied by a structural change that helps relieve the frustration. Analysis of high-resolution synchrotron X-ray scattering reveals that the low-temperature structures are well described by a two-phase model of tetragonal I4_1/amd and orthorhombic Fddd symmetries. The Cr_4 tetrahedra of the pyrochlore lattice are distorted at these low-temperatures, with the Fddd phase displaying larger distortions than the I4_1/amd phase. The spin-Jahn-Teller distortion is approximately one order of magnitude smaller than is observed in first-order Jahn-Teller spinels such as NiCr_2O_4 and CuCr_2O_4. In analogy with NiCr_2O_4 and CuCr_2O_4, we further suggest that the precise nature of magnetic ordering can itself provide a second driving force for structural change.

References in corpus (5)

• Spin-phonon coupling in antiferromagnetic chromium spinels
• Spin-induced symmetry breaking in orbitally ordered NiCr_2O_4 and CuCr_2O_4
• Magnetic phase evolution in the spinel compounds Zn${}_{1-x}$Co${}_x$Cr${}_2$O${}_4$
• Spin phonon coupling in frustrated magnet CdCr${}_2$O${}_4$
• Total scattering descriptions of local and cooperative distortions in the oxide spinel (Mg,Cu)Cr2O4 with dilute Jahn-Teller ions

Cited by in corpus (11)

• Magnetic excitations of the classical spin liquid MgCr2O4
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• Structural distortion below the Néel temperature in spinel GeCo${}_2$O${}_4$
• Structural ground states of ($A,A^{\prime }$)Cr${}_2$O${}_4$($A$=Mg, Zn; $A^{\prime }$ = Co, Cu) spinel solid solutions: Spin-Jahn-Teller and Jahn-Teller effects
• Structural evolution and skyrmionic phase diagram of the lacunar spinel GaMo${}_4$Se${}_8$
• Classical Spin Nematic Transition in LiGa${}_{0.95}$In${}_{0.05}$Cr${}_4$O${}_8$
• Manifolds of magnetic ordered states and excitations in the almost Heisenberg pyrochlore antiferromagnet MgCr2O4
• Magnetic and Structural Phase Transitions in the Spinel Compound Fe1+xCr2-xO4
• Complex magnetic phase diagram with a small phase pocket in a three-dimensional frustrated magnet CuInCr${}_4$S${}_8$
• Orientation-dependent stabilization of MgCr${}_2$O${}_4$ spinel thin films
• Three-dimensional checkerboard spin structure on a breathing pyrochlore lattice