Laboratoire Léon Brillouin
UMR12 CEA-CNRS, Bât. 563 CEA Saclay
91191 Gif sur Yvette Cedex, France
+33-169085241 llb-sec@cea.fr
Small-angle part of the neutron diffraction patterns of Mn0.86Co0.14Ge at 10K at different pressures
N. Martin, M. Deutsch, T. C. Hansen, M. T. Fernandez-Diaz, L. N. Fomicheva, A. V. Tsvyashchenko, and I. Mirebeau
In the MnGe chiral magnet, the helimagnetic order and local moment collapse in two steps, showing the succession of high spin (HS) and low spin (LS) states as pressure increases. Here, we use high-pressure neutron diffraction to study the doped compounds Mn0.86Co0.14Ge and Mn0.9Rh0.1Ge, and show that the evolution of their microscopic magnetic properties is instead continuous. It means that the bulk HS-LS transition is a unique feature of pure MnGe, very sensitive to small changes of the band structure and easily suppressed by chemical substitution. On the other hand, the helimagnetic correlations appear to be strengthened by doping and survive up to larger pressures (≈19 GPa, to be compared with ≈13 GPa). We discuss these results in the light of other disordered systems with remarkable properties, the so-called Invar alloys.
• Systèmes complexes et transition énergétique › Physique statistique et systèmes complexes Statistical physics and complex systems
• Laboratoire Léon Brillouin (LLB) • Leon Brillouin Laboratory (LLB)
• Diffraction poudres • Nouvelles frontières dans les matériaux quantiques - NFMQ
• Neutrons • Diffractomètres poudre (3T2, G41 et G61) • Neutrons • Powder diffraction