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Magnetic-susceptibility measurements, nuclear magnetic resonance (NMR) of (super 11)B, and electron magnetic-resonance (EMR) spectra of YCO3B2 are measured as a function of the temperature. The temperature dependence of the magnetic susceptibility reveals a lambda-shaped anomaly at 150 K.

Magnetic-susceptibility measurements, nuclear magnetic resonance (NMR) of 11B, and electron magnetic-resonance (EMR) spectra of YCo3B2 were measured as a function of the temperature. The temperature dependence of the magnetic susceptibility showed a lambda-shaped anomaly at 150 K. Whereas upon cooling, a shift in the resonance position of the NMR and EMR spectra is observed at 150 K, marking the emergence of an internal magnetic field. The quadrupolar splitting of the NMR lines showed a marked discontinuity at 150 K. The (T1T)-1/2 values were found to be independent of temperature for T>175 K, and to increase sharply upon cooling for T<150 K. The intensity of the EMR line which is independent of temperature for T>160 K is also found to increase markly upon cooling below 150 K. All these effects are discussed and it is proposed that YCo3B2 undergoes a magnetic ordering phase transition at 150 K. [ABSTRACT FROM AUTHOR]

The electronic properties of the intermetallic compound HfCo3B2 were investigated using combined TDPAC measurements and first principles LAPW calculations. The V zz value at the hafnium site is determined from dominant positive p– p contribution, with less than 20%, negative s– d and d– d contributions. Based on the calculated density of state (DOS) at 0 K, a band contribution ( γ band) of 7.26 (mJ/mol/K2) to the value of the electronic specific heat coefficient ( γ) was obtained. This relatively low γ band value is attributed to the hybridization between hafnium d-states, boron 2 p-states and cobalt 3 d-states, formed at the energy interval below E Fermi. This hybridization, together with the dip in the DOS around E Fermi, implies a possible reduction of the low temperature magnetic moment in this compound. [ABSTRACT FROM AUTHOR]

Abstract: AC-susceptibility measurements for HoCo3B2 show paramagnetism below room temperature and a small, and large anomalies at 150 and 10K, respectively. Neutron powder diffraction measurements show a ferromagnetic order below 10K, where the ferromagnetic Ho and Co sublattices are ferromagnetically coupled. The magnetic axis direction is perpendicular to the c axis. The observed magnitudes of the magnetic moments at 4.5K are 5.08(4) and 0.11(2) for Ho and Co, respectively. No long range magnetic order was detected above 10K. [Copyright &y& Elsevier]

The electronic properties of the intermetallic compound HfCo3B2 were investigated using combined TDPAC measurements and first principles LAPW calculations. The V zz value at the hafnium site is determined from dominant positive p– p contribution, with less than 20%, negative s– d and d– d contributions. Based on the calculated density of state (DOS) at 0 K, a band contribution ( γ band) of 7.26 (mJ/mol/K2) to the value of the electronic specific heat coefficient ( γ) was obtained. This relatively low γ band value is attributed to the hybridization between hafnium d-states, boron 2 p-states and cobalt 3 d-states, formed at the energy interval below E Fermi. This hybridization, together with the dip in the DOS around E Fermi, implies a possible reduction of the low temperature magnetic moment in this compound. [ABSTRACT FROM AUTHOR]