Magnetic and atomic order in the potential half metallic ferromagnets Ru2−xFexCrGe

• Published in: Journal of physics. Condensed matter Vol. 20; no. 45; pp. 455201 - 455201 (6)
• Main Authors: Brown, P J, Gandy, A P, Kanomata, T, Kusakari, Y, Sheikh, A, Neumann, K-U, Ouladdiaf, B, Ziebeck, K R A
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 12.11.2008; Institute of Physics
• Subjects: Alloys; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Magnetic properties and materials; Physics; Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.); Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Antiferromagnetism; Cubic lattices; Band structure; Magnetization; Neutron diffraction; Magnetic ordering; Spontaneous magnetization; Magnetic moments; Ruthenium alloys; Iron alloys; Magnetically soft alloy; Chromium alloys; Germanium alloys; Heusler alloys; Lead alloys; Semimetals; Chemical composition; Atomic structure
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/20/45/455201

Neutron powder diffraction and magnetization measurements have been used to study the crystallographic and magnetic properties of Ru2-xFexCrGe with x = 0, 1.0 and 1.7. Ru2CrGe was found to have the Heusler L21 structure and to order antiferromagnetically below TN = 16.5 K to a face centred cubic type 2 structure, propagation vector. Only the Cr atoms carry a magnetic moment, which is oriented perpendicular to the propagation vector and has magnitude 1.45 muB at 5 K. Replacement of Ru by Fe causes the alloys to become ferromagnetic with accompanying disorder amongst the Fe, Cr and Ru atoms with only the Ge atoms remaining completely ordered. Both the neutron diffraction data and the magnetization results for the ferromagnetic alloys lead to non-integral values of the magnetic moment per formula unit differing significantly from the 2 muB predicted by band structure calculations. The materials can therefore not be expected to display ideal half metallic ferromagnetic properties.