Magnetic orders and spin-flop transitions in the cobalt doped multiferroic $$\rm Mn_{1-x}Co_{x}WO_4$$

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Physical Review B

OSTI ID:1081955

Chi, Songxue ^[1]; Fernandez-Baca, Jaime A ^[1]; Cao, Huibo ^[1]; Liang, K. C. ^[2]; Wang, Y. Q. ^[2]; Lorenz, Bernd ^[2]; Chu, C. W. ^[2]

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1. ORNL
2. University of Houston, Houston

We present a comprehensive single crystal neutron diffraction investigation of the $$\rm Mn_{1-x}Co_{x}WO_4$$ with $$0.02\leq x \leq0.30$$. At lower concentration $$x \leq 0.05$$, the system is quickly driven into the multiferroic phase with spin structure forming an elliptical spiral order similar to the parent compound. The reduction of electric polarization is ascribed to the tilting of the spiral plane. For $$x\sim 0.075$$, the magnetic structure undergoes a spin flop transition that is characterized by a sudden rotation of the spin helix envelope into the $ac$ plane. This spin structure persists for concentration up to $x=0.15$, where additional competing magnetic orders appear at low temperature. For $$0.17 \leq x \leq 0.30$$, the system experiences another spin flop transition and recovers the low-$$x$$ spiral spin configuration. A simple commensurate spin structure with $$\vec{q}=(0.5,0,0)$$ is found to coexist with the incommensurate spiral order. The complex evolution of magnetic structure in Co doped $$\rm MnWO_4$$ contrasts sharply with other transition metal ion doped $$\rm Mn_{1-x}A_xWO_4$$ (A=Zn, Mg, Fe) where the chemical substitutions stabilize only one type of magnetic structure. The rich phase diagram of $$\rm Mn_{1-x}Co_{x}WO_4 $$ results from the interplay between magnetic frustration and spin anisotropy of the Co ions.

• Research Organization: Oak Ridge National Laboratory (ORNL); High Flux Isotope Reactor
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1081955
• Journal Information: Physical Review B, Journal Name: Physical Review B Vol. 86
• Country of Publication: United States
• Language: English