Strong Enhancement of Magnetic Coercivity Induced by Uniaxial Stress.

The performance of permanent magnets is intricately tied to their magnetic hysteresis loop. In this study, we investigate the heavy-fermion ferromagnet CeAgSb_{2} through magnetization measurements under uniaxial stress. We observe a 2400% increase in magnetic coercivity with just a modest stress of approximately 1 kbar.

Utilizing frustration in Gd- and Yb-based oxides for milli-Kelvin adiabatic demagnetization refrigeration.

The manifold of energetically degenerate configurations arising from competing interactions in frustrated magnets gives rise to an enhanced entropy at lowest temperatures, which can be utilized for adiabatic demagnetization refrigeration (ADR). We review structural and magnetic properties of various Yb- and Gd-based oxides featuring frustration related to different triangular moment configurations and (in some cases) structural randomness. In comparison to paramagnetic hydrated salts, which have traditionally been employed for mK-ADR, these novel ADR materials enable cooling to temperatures several times lower than the magnetic interaction strength, significantly enhancing the entropy density and cooling power at a given target temperature.

Strong Terahertz Third-Harmonic Generation by Kinetic Heavy Quasiparticles in CaRuO_{3}.

We report on time-resolved nonlinear terahertz spectroscopy of a strongly correlated ruthenate, CaRuO_{3}, as a function of temperature, frequency, and terahertz field strength. Third-harmonic radiation for frequencies up to 2.1 THz is observed evidently at low temperatures below 80 K, where the low-frequency linear dynamical response deviates from the Drude model and a coherent heavy quasiparticle band emerges by strong correlations associated with the Hund's coupling.

Tailoring of magnetism & electron transport of manganate thin films by controlling the Mn-O-Mn bond angles via strain engineering.

Strain engineering beyond substrate limitation of colossal magnetoresistant thin (LaPr)CaMnO (LPCMO) films on LaAlO-buffered SrTiO (LAO/STO) substrates has been demonstrated using metalorganic aerosol deposition technique. By growing partially relaxed 7-27 nm thick heteroepitaxial LAO buffer layers on STO a perfect lattice matching to the LPCMO has been achieved. As a result, strain-free heteroepitaxial 10-20 nm thick LPCMO/LAO/STO films with bulk-like ferromagnetic metallic ground state were obtained.

Antiferromagnetic Correlations in Strongly Valence Fluctuating CeIrSn.

CeIrSn with a quasikagome Ce lattice in the hexagonal basal plane is a strongly valence fluctuating compound, as we confirm by hard x-ray photoelectron spectroscopy and inelastic neutron scattering, with a high Kondo temperature of T_{K}∼480  K. We report a negative in-plane thermal expansion α/T below 2 K, which passes through a broad minimum near 0.75 K.