No abstract

For the investigation of structural, electronic, optical and magnetic properties of Co2CrZ (Z= In, Sb, Sn) compounds, we have used two different methods. One is based on full potential linearized augmented plane wave (FP-LAPW) method as implemented in WIEN2k and second is pseudo potential method as implemented in Atomistic Tool Kit-Virtual NanoLab (ATK-VNL). These compounds show zero band gap in their majority-spin and minority-spin representing metallic behavior except the compound Co2CrSb, which is showing the band gap 0.54 eV in their minority-spin near the Fermi level and viewing 100% spin polarization; which is implemented in WIEN2k code. Further, the compound Co2CrSb has been found to be perfectly half-metallic ferromagnetic (HMF). However, above mentioned compounds shows zero band gap in ATK-VNL code. Calculations performed using WIEN2k code shows the magnetic moment of these compounds Co2CrZ (Z= In, Sb, Sn) 3.11, 5.00 and 4.00µB respectively. However, the respective magnetic moment of these compounds is found to be 3.14, 5.05 and 4.12µB in ATK-VNL code. Calculated magnetic moments have good agreement with the Slater-Pauling behavior. Optical properties play an important role to understand the nature of material for optical phenomenon and optoelectronics devices. Value of absorption coefficient and optical conductivity of Co2CrSb is greatest than other two compounds. From the absorption and reflection spectra relation, observations indicate that absorption and reflectivity are inversely proportional to each other.

In this paper, we have studied the structural, electronic, optical and magnetic properties of Co 2 CrZ (Z= Al, Bi, Ge, Si) compounds by using two different methods one is full potential linearized augmented plane wave (FP-LAPW) method as implemented in WIEN2k and second is pseudo potential method as implemented in Atomistic Tool Kit-Virtual NanoLab (ATK-VNL). The respective band gaps in their minority-spin of Co 2 CrZ (Z= Al, Bi, Ge, Si) are 0.696, 0.257, 0.602 and 0.858 eV near the Fermi level, which is implemented in WIEN2k code and showing 100% spin polarization. Further, these compounds have been found to be perfectly half-metallic ferromagnetic (HMF). However, above mentioned compounds shows zero band gaps in ATK-VNL code. The calculated magnetic moment of these compounds Co 2 CrZ (Z= Al, Bi, Ge, Si) are 3.06, 4.99, 3.99 and 3.99µ B respectively in FP-LAPW method. However, the respective magnetic moment of these compounds is found to be 3.14, 5.08, 4.11 and 4.08µ B in ATK-VNL code. Optical properties play an important role to understand the nature of material whether it can be used as optoelectronics device. From the optical Spectra, complex dielectric functions calculated values are 312. 370 and 141.991, 299.812 and 111.368, 288.127 and 106.342, 290.688 and 99.095 for the compounds Co 2 CrZ (Z= Al, Bi, Ge, Si) respectively by using WIEN2k. The maximum energy loss is observed between 11.4 to 13eV for above these compounds. The refractive index values for the compounds Co 2 CrZ (Z= Al, Bi, Ge, Si) are observed as 18.104, 17.602, 17.252 and 17.289 respectively. In the optical conductivity spectrum a sharp peak is observed at 1.6 -2.3eV.

No abstract

Herein, optoelectronic, elastic and magnetic properties of L21 structured Co2VZ (Z= Pb, Si, Sn) full Heusler compounds have been investigated by two methods. One is full potential linearized augmented plane wave (FP-LAPW) method as implemented in WIEN2k and second is pseudo potential method as implemented in Atomistic Tool Kit-Virtual NanoLab (ATK-VNL). All these compounds shows zero band gap in majority spin channel in the both simulation codes and a finite band gap are 0.33 and 0.54 eV in Co2VZ (Z= Pb, Sn) alloys (semiconducting) respectively. Due to minority-spin channel near the Fermi level as implemented in WIEN2k code and showing 100% spin polarization except Co2VSi (metallic) with zero band gap. These compounds found to be perfectly half-metallic ferromagnetic (HMF). However, above mentioned compounds shows finite band gaps in ATK-VNL code. The calculated magnetic moment of these compounds Co2VZ (Z= Pb, Si, Sn) are 3.00 and 3.00, 3.02 and 2.96, 3.00 and 3.00µB in WIEN2k and ATK-VNL codes respectively. Thus we have observed that the calculated vales by these simulation codes and Slater-Pauling rule have nice tuning. Optical properties of these compounds like as reflectivity, refractive index, excitation coefficient, absorption coefficient, optical conductivity and electron energy loss have been analyzed. Absorption coefficient and electron energy - loss function values are increases as we increase the value of energy. The vales of Pugh’s ratio B/G is greater than 1.75 for all compounds and showing ductile nature with positive value of Cauchy pressure (CP = C12 – C44) and shows metallic behavior of Co2VZ (Z= Pb, Si, Sn) compounds.