This work is a study of the microstructural properties of the polycrystalline ternary compounds AgIn5S8, AgIn5Se8, and AgIn5Te8 by X-ray diffraction technique (XRD). The full-width-half-maximum (FWHM) of the XRD profile is measured as function of the diffraction angle and used to estimate the microstructural parameters. In general, a microstructural characterization by XRD is principally performed by Strain/Size analysis based on the modified Scherrer formula, which in turn, allows for mean grain size and average microstrain to be computed. However, when applied to polycrystalline bulk semiconductors, the modified Scherrer formula gives grain sizes of the order of a few hundreds of nanometers, which is not usually observed in bulk materials. Instead, a new theoretical scheme with misfit dislocations and plastic deformations would be used to calculate the grain size into a bulk. Assuming that these dislocations are of elastic origin, we were able to calculate the misfit dislocations density as function of the elastic constants of the materials. With this, the modified Scherrer formula is corrected to explain the additional XRD line broadening. All microstructure parameters of our samples increase as the atomic radius of the VI-element increases, with elastic constants similar to related semiconducting compounds.

Abstract Here we report on the effect of the ferromagnetic (FM) and antiferromagnetic (AF) films thicknesses on the exchange bias field in a FM/AF bilayer. For this, a series of NiFe(t NiFe)/NiO(t NiO) bilayers were grown by DC magnetron sputtering onto commercial Si(001) wafers. Magneto-optical hysteresis loops were used as probes to measure the exchange-bias field, and the coercivity field, as functions of the in-plane angle, φ H, and the films’ thicknesses, t NiFe and t NiO. The in-plane symmetry of the exchange field and coercivity display unidirectional and uniaxial anisotropies, with angular dependences different from the simple c o s φ H and c o s 2 φ H, respectively. These symmetries are intrinsically sensitive to the thickness of both NiFe and NiO layers. With respect to the FM layer thickness, the exchange bias and coercivity field follow the usual 1/t NiFe, while the dependence on the thickness of the AF layer is more complicated, and is characterized by a critical behavior.

Reportamos evidencia experimental de polarización de intercambio entre una película ferromagnética (FM) de Fe4.6Co7(0.4)Si15B10 y una de NiO antiferromagnética (AF), depositadas sobre substratos de Si(001). Se obtuvieron las curvas de histéresis utilizando la técnica de Efecto Kerr Magnetoóptico de Superficie (SMOKE), y medimos el desplazamiento de las curvas y el campo coercitivo en función del ángulo acimutal, φH, y el espesor de la película FM, t. Las medidas revelan la presencia de anisotropías unidireccional y uniaxial, cuyas asimetrías corresponden a funciones complejas de cos(φH), y dependencia con el espesor proporcional a 1/t, típica de los efectos de interface.

We report on experimental evidence of exchange bias between the amorphous ferromagnetic (FM) Fe4.6Co70.4Si15B10 and an antiferromagnetic (AF) NiO film, grown onto single crystalline Si(001) wafers. Surface Magneto-optic Kerr Effect (SMOKE) has been used to measure the hysteresis loop shift, and coercivity, as functions of the azimuthal angle, φH, and the FM layer thickness, t. The measurements reveal the presence of induced unidirectional and uniaxial symmetries following a complex cosine dependence, and thickness dependence proportional to 1/t, typical of interfacial effects.