Electronic and Magnetic Properties of MAX Phase (Cr1-xGdx)2AlC and Er3AlC Alloy
Albandri, Huriyyah A
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Bulk samples of (Cr1-xGdx)2AlC with X = 0, 0.0025, 0.01, 0.025, 0.05 and Er3AlC compound were synthesized using the arc melting technique. The samples were characterized by X-ray diffraction, magnetic susceptibility, and four probe resistivity measurements to study their magnetic and electronic properties. Using Rietveld analysis for X-ray diffraction, it was determined that the parent compound Cr2AlC exhibits a side phase of Cr7C3. The substituted samples were found to have secondary phases of Cr7C3 and GdCr3.5Al8.5 which slightly increase on increasing substitution of Cr3+ by Gd3+. The change of the concentration of Gadolinium does not have any real effect on the lattice parameter of (Cr1-xGdx)2AlC. Er3AlC contains secondary phases of ErAl2 and ErC0.6. The MAX phase Cr2AlC and the Gadolinium substituted samples show complex magnetic behaviour. The magnetization measurements show that Cr2AlC has an unusual magnetic behavior above 70 K which does not obey the Curie-Weiss law. The sample with X = 0.0025 also does not obey the Curie-Weiss law at high temperature. The susceptibility data shows that samples with X = 0.01, 0.025, and 0.05 obey the Curie-Weiss law, and the magnitude of the effective magnetic moments decreases while increasing the value of X. The susceptibility data of Er3AlC obey the Curie-Weiss law; and the effective moment is 9.1 ± 0.005 𝛍B. The resistivity measurement of the parent sample Cr2AlC indicates metallic behavior. In the Gd-substituted samples, we observed a Kondo Effect from the resistivity data. The resistivity of Gd-substituted samples increases with increasing Gadolinium concentration. We also observed metallic behavior in the Er3AlC resistivity.