Giant magnetic-field changes in radio-frequency absorption in La0.67Sr0.33MnO3 near the Curie temperature

Abstract

The DC transport properties of and the radio-frequency (RF) wave absorption (at 2:525 MHz) in a sample of La 0:67 Sr 0:33 MnO 3 prepared by floating-zone method are measured. The Curie temperature, T c ; of the sample is about 374 K: Giant temperature and magnetic-field variations in RF absorption are found in the vicinity of T c : Relative change of the RF absorption in magnetic field (magnetoabsorption) is about 67% in field 2:1 kOe and about 55% in field 1 kOe: This giant magnetoabsorption effect can be used to develop RF devices controlled by temperature and low magnetic field. A weak temperature dependence of magnetoabsorption for the sample studied in the range from room temperature to about 350 K makes it especially attractive for practical use. The RF study supplemented with transport, magnetoresistive and magnetic measurements enables us to discuss the optimal properties of manganite samples for observation of giant magnetoabsorption in low field. r

Extrinsic inhomogeneity effects in magnetic, transport and magnetoresistive properties of () crystal prepared by the floating-zone method

“…As shown by previous experience [8], manganite crystals produced by this technique are almost single crystals, and, in this respect, they have far better crystal quality and far less porosity than samples prepared by a solid-state reaction technique. On the other hand, the crystals have twin domain structure and may have a few grain boundaries.…”

Giant magnetoimpedance and high frequency electrical detection of magnetic transition in La0.75Sr0.25MnO3

“…The observed value of ac magnetoresistance (≈19% at 65 mT for f = 4 MHz) is much larger than the dc magnetoresistance. Our observed value of ac magnetoresistance is also larger than that given in a previous report (≈8% at 80 mT for 5 MHz ) by Qin et al [7] and magneto transmission study (≈6% in H = 0.3 T) by Belevtsev et al [8]. In contrast to Z /Z , the maximum magnitude of Z /Z is ≈15% at 2 MHz , which is comparable in magnitude but lower in frequencies as shown in figure 3(a).…”

The influence of tilt angle on the CMR in Sm0.6Sr0.4MnO3

“…After this temperature (T ∼ 74 K) a metallic behavior is observed. This behavior is similar to electron or hole doped manganites [18][19][20][21][22]. A hysteresis between heating and cooling of ρ(T) is characterized.…”