The magnetic and transport properties of the Co₂FeGa Heusler alloy

Abstract

The magnetic and transport properties of the Co2FeGa Heusler alloy have been investigated. The results show that the temperature dependence of the magnetization follows the spin-wave behaviour at low temperature. The electrical resistivity behaves according to a ∼T2 power law, which may be mainly attributed to electron–electron scattering, and the contribution of electron–phonon scattering to the resistivity seems to be small. We have not observed remarkable magnetoresistance in our measurements. Point contact Andreev reflection measurements of the spin-polarization yield a polarization of 59%, which is consistent with the theoretical prediction by a first-principles calculation.

Magnetic properties and phase stability of half-metal-type Co2Cr1−xFexGa alloys

“…The Curie temperature T c rises and that of Co 2 FeGa is almost the same as the transition temperature from the L2 1 -to B2-type phase T t B2/L2 1 , while T t B2/L2 1 hardly varies with increasing x. The concentration dependence of the saturation magnetic moments M s measured at 4.2 K for Co 2 Cr 1−x Fe x Ga alloys together with the other experimental data [10,13,16] is compared with the data of Co 2 Cr 1−x Fe x Al alloys [12], as shown in Fig. 2.…”

“…2. Concentration dependence of the saturation magnetic moments measured at 4.2 K for Co 2 Cr 1−x Fe x Ga alloys, together with other experimental data [10,13,16], compared with the data of Co 2 Cr 1−x Fe x Al alloys [12]. The dotted line gives the generalized Slater-Pauling line of M t = Z t − 24, where M t and Z t represent the total spin magnetic moment per formula unit and the total number of valence electrons, respectively [6,17].…”

Structural, magnetic and transport properties of half-metallic ferrimagnet Mn2VGa

“…Within the parabolic magnon band structure the magnetic moment varies as T 3/2 for ideal localized magnetic moment systems (Heisenberg-type ferromagnet). The half-metallic gap decreases very rapidly with temperature compared with the magnetic splitting, resulting in the vanishing of the gap well below the Curie temperature (o80 K) [18][19][20]. We have fitted the temperature dependence of spontaneous magnetization below 80 K to a function M s (T) ¼ M s (0)[1ÀAT 1.5 ] which assumes the parabolic magnon-dispersion relation (h/2p)o ¼ DK 2 (D is the spin-wave stiffness coefficient) (Fig.…”

Magnetic properties and spin polarization of Co2Mn(SixSn1−x) alloys containing two L21 phases

“…PCAR studies show that P ≤ 0.60 in the ternary Heusler alloys [13][14][15][16][17][18], although TMR measurements using Co 2 MnSi has shown a tunneling spin polarization (P t ) of 0.89 [6]. We have successfully used this technique to identify several full Heusler alloys [8,17,18] with high intrinsic spin polarization such as Co 2 Fe(Ga 0.5 Ge 0.5 ) [19].…”