Ab-initio calculation of effective exchange interactions, spin waves, and Curie temperature in L2_1- and L1_2-type local moment ferromagnets

Abstract

Employing first-principles electronic structure calculations in conjunction with the frozen-magnon method we study the effective exchange interactions and spin waves in local moment ferromagnets. As prototypes we have chosen three L2${}_1$-type full Heusler alloys Cu${}_2$MnAl, Ni${}_2$MnSn and Pd${}_2$MnSn, and the L1${}_2$-type XPt${}_3$ compounds with X= V, Cr and Mn. We have also included CoPt${}_3$ which is a usual ferromagnet. In all compounds due to the large spatial separation ($\sim 4$ Å) of the magnetic transition metal atoms, the 3\textit{d} states belonging to different atoms overlap weakly and as a consequence the exchange coupling is indirect, mediated by the \textit{sp} electrons. Calculated effective exchange parameters are long range and show RKKY-type oscillations. The spin-wave dispersion curves are in reasonable agreement with available experimental data. Using the calculated exchange parameters we have estimated the Curie temperatures within both the mean-field and the random-phase approximations. In local moment ferromagents deviations of the estimated Curie temperature with respect to the available experimental data occur when the ground-state electronic structure calculations overestimate the values of the spin magnetic moments as in VPt${}_3$.

Submitted for a Special Issue of Journal of Materials Science entitled "Recent Advances in First Principles Computations in Materials Research "

References in corpus (7)

• Role of the conduction electrons in mediating exchange interactions in Heusler alloys
• Ab-initio design of half-metallic fully-compensated ferrimagnets: the case of Cr${}_2$MnZ (Z= P, As, Sb, Bi) compounds
• Exchange interactions and Curie temperatures in Mn2CoZ compounds
• Electron correlations in Co${}_2$Mn${}_{1-x}$Fe${}_x$Si Heusler compounds
• Ab initio prediction of ferrimagnetism, exchange interactions and Curie temperatures in Mn2TiZ Heusler compounds
• Nonzero macroscopic magnetization in half-metallic antiferromagnets at finite temperatures
• Magnetism of mixed quaternary Heusler alloys: (Ni,T)${}_2$MnSn (T=Cu,Pd) as a case study

Cited by in corpus (3)

• Calculated magnetic exchange interactions in Dirac magnon material Cu3TeO6
• Spin-resolved Fermi surface of the localized ferromagnetic Heusler compound Cu${}_2$MnAl measured with spin-polarized positron annihilation
• Ab-initio calculation of the Hubbard $U$ and Hund exchange $J$ in local moment magnets: The case of Mn-based full Heusler compounds