Neutron scattering study of role of partial disorder-type spin fluctuations in conductivity of frustrated conductor Mn3_3Pt

The spin-frustrated conductor Mn$_3$Pt exhibits a characteristic magnetic structure called partial disorder in which some spin sites can form magnetic order through the generation of non-ordered sites that locally relieve the frustration. Here we report the results of a single-crystal inelastic neutron scattering study of this compound. The measured momentum $\vec{Q}$ correlations of diffusive magnetic scattering reveal that the paramagnetic phase exhibits short-range spin fluctuations with the same type of partial disorder. Its relation to conductivity is also discussed.Comment: 5 pages, 4 figure

NEUTRON DIFFRACTION STUDY OF ORDERED Mn-ALLOYS

Dans le système Mn-Pd on a trouvé que la surstructure de longue période avec des domaines d'antiphase existe jusqu'à 36 at % Mn. En augmentant la concentration de Mn la période croît mais la configuration antiferromagnétique reste inchangée. Dans les échantillons refroidis lentement une autre phase antiferromagnétique apparaît, son point de Néel est plus élevé que celui de la structure des domaines d'antiphase dans le même échantillon. Dans le système Mn3PtNx les atomes d'azote sur les positions intersticielles du motif de type Cu3Au dilatent la maille, donc la température de la transformation triangulaire-colinéaire antiferromagnétique, observée antérieurement dans Mn3Pt, décroît si la concentration de l'azote augmente. La valeur du moment magnétique sur les atomes Mn change dans la transformation triangulaire-colinéaire.In the Mn-Pd system the long-period antiphase domain structure was found to exist up to 36 at % Mn-with increasing Mn concentrations the period increases while the antiferromagnetic configuration remains unchanged. In slowly cooled specimens an additional antiferromagnetic phase appears with a Néel point considerable higher than TN of the antiphase domain structure in the same sample. In the Mn3PtNx system the nitrogen atoms at the interstitial positions of the Cu3Au type cell cause the lattice to dilate, thus the temperature of the traingular-collinear antiferromagnetic transition, observed earlier in Mn3Pt, decreases with increasing N-concentration. A change in the value of the magnetic moment on the Mn atoms is observed in the triangular-collinear transformation