Ferromagnetic resonance measurement with frequency modulation down to 2 K.

Ferromagnetic resonance (FMR) spectroscopy is a powerful technique to study the precessional dynamics of magnetization in thin film heterostructures. It provides valuable information about the mechanisms of exchange bias, spin angular momentum transfer across interfaces, and excitation of magnons. A key desirable feature of FMR spectrometers is the capability to study magnetization dynamics over a wide phase space of temperature (T), frequency (f), and magnetic field (B).

Competition between electron pairing and phase coherence in superconducting interfaces.

In LaAlO/SrTiO heterostructures, a gate tunable superconducting electron gas is confined in a quantum well at the interface between two insulating oxides. Remarkably, the gas coexists with both magnetism and strong Rashba spin-orbit coupling. However, both the origin of superconductivity and the nature of the transition to the normal state over the whole doping range remain elusive.

Crossover from magnetostatic to exchange coupling in LaCaMnO/YBaCuO/LaCaMnO heterostructures.

The influence of YBaCuO (YBCO) superconductor layer (S-layer) with a varying thickness d   =  20-50 nm on the magnetic coupling between two LaCaMnO (LCMO) ferromagnet layers (F-layer, thickness d   =  50 nm) in F/S/F heterostructures (HSs) was investigated by measuring global magnetization (M) in a temperature (T) range  =  2-300 K and a magnetic field (H) range  =  0-10 kOe. All the HSs were superconducting with the critical temperature (T ) decreasing from  =  78 to 36 K with decrease in d , whereas the ferromagnetic ordering temperature T   =  250 K did not change much. Systematically measured M-H loops of all HSs at both T  >  T and T  <  T show three main results (a) the two step magnetic reversal above T converts into a four step reversal below T in HSs with d   ⩾  30 nm, (b) the magnitude and magnetic field corresponding to the additional two switching steps show characteristic evolution with T and d ; and (c) the HS with d   =  20 nm shows radically different behaviour, where the two step magnetic reversal above T continues to persist below T and converts into a single step reversal at T [Formula: see text] T .

Note: Fiber optic transport probe for Hall measurements under light and magnetic field at low temperatures: Case study of a two dimensional electron gas.

A fiber optic based probe is designed and developed for electrical transport measurements in presence of quasi-monochromatic (360-800 nm) light, varying temperature (T = 1.8-300 K), and magnetic field (B = 0-7 T). The probe is tested for the resistivity and Hall measurements performed on a LaAlO3-SrTiO3 heterointerface system with a conducting two dimensional electron gas.

Enhanced spin-orbit coupling and charge carrier density suppression in LaAl1-xCrxO3/SrTiO3 hetero-interfaces.

We report a gradual suppression of the two-dimensional electron gas (2DEG) at the LaAlO(3)/SrTiO(3) interface on substitution of chromium at the Al sites. The sheet carrier density at the interface (n□) drops monotonically from ∼2.2 × 10(14) cm(-2) to ∼2.