arXiv subjects

Anna Merin Francis

Publications and source records attributed to Anna Merin Francis.

3 recordsLinked to original sources

arXiv2026

Optimized Broadband Cryogenic Ferromagnetic Resonance Spectrometer using a Closed Cycle Refrigerator

We present a vector network analyzer (VNA) based broadband cryogenic ferromagnetic resonance (FMR) spectrometer, operating up to 20 GHz over a temperature range of 11 to 350 K. A cost effective architecture is implemented through the integration of a closed cycle refrigerator (CCR) and a custom fabricated grounded coplanar waveguide (GCPW), designed for broadband transmission and reliable cryogenic operation. The VNA calibration is performed prior to measurements to account for microwave background and transmission losses, enabling reliable extraction of FMR spectra across the full temperature / frequency range. The sensitivity of the spectrometer is benchmarked using a yttrium iron garnet (YIG) thin film, yielding well resolved resonances with narrow linewidths and high sensitivity.

physics.ins-det↗

arXiv2025

Exploring the Anomalous Nernst Effect in SrRuO$_3$

We investigate the anomalous Nernst effect in epitaxial SrRuO$_3$ thin films grown on c-cut Al$_2$O$_3$ substrates, and in a polycrystalline SrRuO$_3$ slab. Through comprehensive measurements of the transverse thermoelectric response as a function of temperature and magnetic field, we observe a pronounced Nernst signal near $T_c$ in the (111) oriented SrRuO$_3$ thin films. The strong temperature and nontrivial field dependence underscore the pivotal role of the magnetic anisotropy in tuning the Berry curvature and, consequently, the anomalous Nernst effect in SrRuO$_3$.

cond-mat.str-el↗

arXiv2025

Magnon Spin Current Modulation through Site-Specific Doping in a Compensated Iron Garnet

We report on the impact of manganese doping at the iron sites in Gadolinium Iron Garnet (GdIG, Gd$_{3}$Fe$_{5}$O$_{12}$), employing temperature-dependent spin Seebeck effect and ferromagnetic resonance measurements. Our findings reveal a clear shift in the magnetic compensation temperature ($T_{comp}$) in Mn-doped GdIG, with minimal changes observed in the magnetic and damping properties. Notably, the spin Seebeck signal strength was enhanced significantly with the Mn doping. This enhancement is attributed to an increased spin mixing conductance and modifications in the magnon spectra that strengthen exchange interactions, highlighting the material's potential for room-temperature spintronic applications.

cond-mat.str-el↗