Search for ferromagnetism in Hf2Co7: An investigation by perturbed angular correlation (PAC) spectroscopy

Abstract Perturbed angular correlation (PAC) measurements in Hf2Co7 have been performed in the temperature range 77–973 K using the 181Hf probe to observe ferromagnetism in this intermetallic alloy. From present measurements, no magnetic interaction is observed at any temperature in the above temperature range. Only two quadrupole interaction frequencies have been found. At room temperature, values of quadrupole frequency and asymmetry parameter are found to be ω Q = 15.7 ( 4 ) Mrad/s , η = 0 , δ = 0 for site 1 ( ∼ 71%) and ω Q = 46 ( 1 ) Mrad/s , η = 0.74 ( 5 ) , δ = 5 ( 3 ) % for site 2 ( ∼ 29%). Present results contradict with the earlier reported results where a room temperature ferromagnetism was found with a Curie temperature of ∼ 400 K. X-ray diffraction measurement in Hf2Co7 has also been performed. From the measured XRD pattern, an almost pure phase of Hf2Co7 was observed.