Ultrasonic investigation of the re-entrant superconductors and the ferromagnetic compounds of Er/sub 1-x/Ho/sub x/Rh/sub 4/B/sub 4/ system

Thesis/Dissertation · Wed Jan 01 00:00:00 EST 1986

OSTI ID:5312918

Sun, K J

The ultrasonic attenuation coefficient in the normal, superconducting, paramagnetic, and ferromagnetic states of polycrystalline samples of Er/sub 1-x/Ho/sub x/Rh/sub 4/B/sub 4/ system with X = 0, 0.295 0.6, 0.813, 0.912 and 1 was measured as a function of temperature at constant applied magnetic fields and as a function of magnetic field at constant temperatures. Results show the following characteristics: (1) For all samples, a bell-shaped maximum observed on each of the temperature-dependent attenuation curves is believed to be a relaxation-type attenuation maximum associated with splitting of the ground state of magnetic ions. (2) In the superconducting state of the re-entrant superconductors, Er/sub 0.4/Ho/sub 0.6/Rh/sub 4/B/sub 4/ and Er/sub 0.187/Ho/sub 0.813/Rh/sub 4/B/sub 4/, the attenuation increases as the temperature is lowered from the normal to the transition temperature (T/sub c1/) to the magnetic phase transition temperature (T/sub m/). (3) Temperature-dependent attenuation curves of the ferromagnetic compounds, Er/sub 0.088/Ho/sub 0.912/Rh/sub 4/B/sub 4/ and HoRh/sub 4/B/sub 4/, show relative minima at their T/sub m/'s, which illustrates that there are no critical spin fluctuations at temperatures close to and at T/sub m/. (4) For the Er/sub 0.705/Ho/sub 0.295/Rh/sub 4/B/sub 4/ sample, the temperature and magnetic-field-dependent data display characteristics consistent with theoretical predictions leading to the conclusion there is a coexistence state of superconductivity and long-range magnetic order in the range between 0.99 and 1.31 K

• Research Organization: Wisconsin Univ., Milwaukee (USA)
• OSTI ID: 5312918
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON ALLOYS
MAGNETIC PROPERTIES
SUPERCONDUCTIVITY
ERBIUM ALLOYS
HOLMIUM ALLOYS
RHODIUM ALLOYS
FERROMAGNETISM
PARAMAGNETISM
ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
MAGNETISM
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
RARE EARTH ALLOYS
360104* - Metals & Alloys- Physical Properties