Enhanced magnetoelastic stress in disordered iron-gallium alloy thin films revealed by direct measurement

[Description of methods used for collection/generation of data] RHEED images (files starting with Fig1b) were collected using a digital camera UK1117m equipped with a Sony ICX415AL sensor. The pixel type is gray with a pixel width of 8 bits and a variable exposure time and gain was used. Film thickness was obtained with a Discover D8 diffractometer with Cu Ka1 radiation (files starting with Fig1c). Bragg-Bentano scans were conducted with a Rigaku X-ray diffraction at Cu Ka radiation. (files starting with Fig1d). Composition was determined using energy-dispersive X-ray spectroscopy (EDX) using a INSPECT-F50 SEM (https://lma.unizar.es/sem-inspect/) and Wavelength Dispersive Spectroscopy (WDS) in an electron probe micro-analyzer (EPMA) instrument (JXA-iHP200F at the Universidad of Zaragoza). Synchrotron X-ray diffraction measurements were conducted at the BM25 beamline of the ESRF synchrotron at room temperature. A monochromatic beam with a wavelength of 0.7 Å was used. (files starting with Fig2). The reference grid is obtained using the MgO reflections of the monocrystalline substrate used to grow the films. Several non-collinear reflections are requested to calculate the matrix elements. Synchrotron XAS measurements were conducted at the Fe and Ga K-edges at beamline I18 of the Diamond UK’s National Light Source at beamline I18 of the Diamond UK’s National Light Source. Magnetization measurements were obtained using nanoMOKE3 magnetometer using laser beam with p-polarization and red (650 nm wavelength) light. High-field lineal correction is applied. Cantilever beam measurements. The magnetoelastic stress was obtained using a cantilever beam method. The sample is clamped by one end, and a constant magnetic field of 100 mT is rotated. The magnetic field is generated by a homemade dipole mounted on a motorized rotatory stage(Standa 8MR190-90-4247). Several turns are performed to correct drifts and other errors. The capacitor is built with the sample that covers a second smaller electrode. The capacitance is measured using an Andeen Hagerling 2500A capacitance bridge at 1kHz. The difference in capacitance with the magnetic field along the beam and forming 90 degrees is used to obtain the magnetoelastic stress. That value is multiplied by the factor indicated in the Appendix. Files starting with Fig6 include the capacitance recollected, Cap, the capacitance with a correction (using a 4-degree polynomial) to eliminate drift, deltaC, the magnetoelastic stress, ME. and the angular position, angle, starting with H along the beam length.