| Sn Mossbauer spectra of the Heusler alloys Pd(,2)MnSb(,1-x)Sn(,x) have been studied in the temperature range 4.2K (LESSTHEQ) T (LESSTHEQ) 295K for three specific compositions x = 1.00, 0.60 and 0.01. The temperature dependence of ('119)Sn internal magnetic field H(T) in Pd(,2)MnSn scales well with the host magnetization M(T) and both can be described well by a spin 3/2 Brillouin curve. However, in Pd(,2)MnSb(,0.99)Sn(,0.01), H(T) is found to decrease more rapidly than M(T) of the Pd(,2)MnSb host which is indicative of a stronger Mn-Sn exchange than a Mn-Sb exchange interaction. For a x = 1.00 sample as well as a x = 0.01 sample, temperature dependence of the recoil-free fraction exhibits an anomalous increase near T(,c) which is interpreted as evidence of lattice hardening due to a magnon-phonon interaction. For a x = 1.00 sample as well as a x = 0.01 sample, temperature dependence of the isomer shift (delta)(T) exhibits an anomalous decrease near T(,c). The physical origin of this effect is believed to be magnetically induced electronic and not phonon associated in character. This electronic effect is most likely due to a delicate repopulation of states as magnetic ordering begins. Profound effect of heat treatment and mechanical treatment on the indicated Heusler alloys is documented by Mossbauer spectroscopy. It is shown that these effects are related to the presence of chemical disorder and point defects in the cubic L2(,1) structure. |
