The transport properties of RCo₂compounds

Abstract

The hansport properties of intermetallic compounds RCo2 (R = Pr, Nd, Sm, Gd-Lu, Sc and U) in the temperahue range f" 4.2 up to 1000 K were studied and different contributions were determined. In the non-magnetic compounds the spin fluchlation conhibution to the elechical resistivity, p,f U ( T / Z f ) z , and themal resistivity. Wsf c( (T/Trf). were found to follow Ihe theoretical predictions. The spin disorder wnuibution arising f" the scattering of conduction elecImns on 4f moments was deduced and found to be proportional to the de Gennes factor. It is shown that the spin fluctuations m responsible for the low-temperame features of the kmperature-dependent thermopower, whereas the high-temperarure behaviour is mainly determined by the density of states function.In the paramagnetic region near the Curie tempen", the critical fluctuations cause a considerable enhancement of the electrical resistivity of the magnetic RCq compounds, which is manifested by pronounced upturns in p versus T dependences.[9, 101. In the following the most important results are summarized.Low temperatures, T c l;f:Electrical resistivity: psf = AT2, with A proportional to TX7'. Magnetoresistance: ( A p / p ) s f is negative and proportional to the square of the appliedThermal resistivity: Wsf = cT, with c proportional to q:'.Thennopower: the situation is not yet clear. In some calculations a minimum below Elevated temperatures:Electrical resistivity: psj saturates somewhat above G,.. According to [9], for high values of the Stoner enhancement factor the resistivity can go through a maximum above i " , followed by a negative slope towards the high-temperature region.Thermal resistivity: Wsf passes a maximum around Tsf and decreases proportional to T-' at higher temperatures. magnetic field. cf has been predicted 1111.. .

Magnetic switching and magnetic transitions in ErCo2 probed by radio-frequency transverse susceptibility

“…Therefore, as the magnetic field is swept from l 0 H sat ¼ 5 T to 0 the change in the sign of the TS profile from negative to positive at l 0 H sat $ 3 T is expected. In summary, our study based on TS measurements on ErCo 2 is coherent with all the previous results from magnetic and transport studies 3,12 confirming the existence of shortrange correlations at T c < T < T f and the power of the technique for studying magnetism at the nanoscale. A remarkable evidence of these correlations was given by probing the existence of a finite H S in the parimagnetic region in ErCo 2 .…”

Magnetic properties ofRFe2Zn20andRCo2Jia1, Ni2, Bud’ko3 et al. 2009Phys. Rev. B7112690View full textAdd to dashboardCite

“…Also appearing in the resistivity of RCo 2 (R = Gd -Tm) [37], this decreasing behavior of For example, Pd manifests T max ∼ 70 K [20]; YCo 2 and LuCo 2 manifests T max ∼ 100 K [21];…”

Identifying the critical point of the weakly first-order itinerant magnet DyCo2with complementary magnetization and calorimetric measurements

“…If that volume change is sufficiently large, the phase transition will be first order 12 and itinerant electron metamagnetism occurs. 13 In DyCo 2 -an IEM of potential interest for low temperature magnetocaloric applications 14 -a first order phase transition was predicted 13,15 and observed by XRD in zero field, where a cubictetragonal distortion occurs alongside the magnetic transition 16,17 (these same XRD measurements…”