Unambiguous determination of the commensurate antiferromagnetic structure of HoNi2B2C in the superconducting ground state

Article

关键词: CRYSTAL-STRUCTURE;    ORTHORHOMBIC DISTORTION;    MAGNETIC ORDER;    PHASE;    EARTH;    DIFFRACTION;    TRANSITION;    GROWTH;   

DOI  :  10.1103/PhysRevB.100.014414

来源: SCIE

【 摘 要 】

Crystal and magnetic structures of the intermetallic HoNi2B2C have been investigated using different single-crystal diffraction techniques at both room and low temperatures (superconducting phase). Combined refinement of the neutron and x-ray diffraction data performed at room temperature shows that the crystal structure of HoNi2B2C is well described in the tetragonal space group 14/mmm, in agreement with the literature. The magnetic ordering at low temperatures is accompanied by a structural phase transition to the orthorhombic space group F mmm. However, only noncharacteristic orbits are occupied in this space group, and the symmetry reduction is entirely due to a lifting of the symmetry-induced restrictions on the anisotropic displacement parameters. Based on magnetic symmetry analysis, two types of commensurate antiferromagnetic structures with different magnetic space groups (MSGs) are found below T-N approximate to 5.2 K: MSG P(i)nnm (Ho spins are along the [100] direction of the parent structure) and MSG C(A)mca (Ho spins are along [110] of the parent structure). Both models agree well with conventional unpolarized neutron diffraction data at low temperature (2.4 K) with ordered magnetic moments of 9.16(9) mu(B)/Ho3+ atom. Spherical neutron polarimetry, on the other hand, allowed us to unambiguously solve the magnetic structure (MSG C(A)mca) as well as to determine the population of two types of 90 degrees antiferromagnetic domains (0.45/0.55).

【 授权许可】

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