Chagovets T.V. «A study of the electric response of HE II at the excitation of second sound waves» Физика низких температур, 42, № 3, с. 230-235 (2016)

We report an experimental investigation of the electric response of superfluid helium. Our results confirm the presence of electric potential that appears at the relative oscillatory motion of normal fluid and superfluid components in helium generated by the heater. The resonance of the electric potential was observed in the first four harmonics. A suggested method for the detection of the electric response allows the required resonance peak to be distinguished from spurious signals. Our results are in qualitative agreement with the data published by previous researchers. The reasons for the discrepancy in the measured values of the potential difference are discussed.

Felea V., Prodan L., Stefanet E., Cong P.T., Zherlitsyn S., Tsurkan V. «Ultrasound propagation in bond frustrated HgCr₂S₄ spinel in magnetic fields» Физика низких температур, 43, № 5, с. 702-706 (2017)

Ultrasound and magnetization studies of bond frustrated spinel HgCr₂S₄ are performed as a function of temperature in static magnetic fields. Beside the anharmonic effect, the sound velocity shows pronounced anomaly at the antiferromagnetic (AFM) transition at T_N=23 K with an additional significant increase of the order of 0.5% indicating a strong spin-lattice coupling. External magnetic fields enhance the ferromagnetic (FM) correlations and shift the anomalies to lower temperatures concomitantly with the reduction of the Neel temperature. The constructed H–T phase diagram beside the long-range AFM states reveals the state with induced FM order and regimes with short-range AFM and FM correlations as well.