The recent literature concerning the magnetocaloric effect (MCE) has been reviewed. The MCE properties have been compiled and correlations have been made comparing the behaviours of the different families of magnetic materials which exhibit large or unusual MCE values. These families include: the lanthanide (R) Laves phases (RM2, where M = Al, Co and Ni), Gd5(Si1−xGex)4 ,M n(As1−xSbx), MnFe(P1−xAsx), La(Fe13−xSix) and their hydrides and the manganites (R1−xMxMnO3, where R = lanthanide and M = Ca, Sr and Ba). The potential for use of these materials in magnetic refrigeration is discussed, including a comparison with Gd as a near room temperature active magnetic regenerator material. (Some figures in this article are in colour only in the electronic version)

https://iopscience.iop.org/article/10.1088/0034-4885/68/6/R04/pdf

Recent developments in magnetocaloric materials

Review of the magnetocaloric effect in manganite materials

Giant and isotropic magnetoresistance as huge as −53% was observed in magnetic manganese oxide La0.72Ca0.25MnOz films with an intrinsic antiferromagnetic spin structure. We ascribe this magnetoresistance to spin‐dependent electron scattering due to spin canting of the manganese oxide.

31p-S-4 Giant Magnetoresistance in Magnetic Manganese Oxide with Intrinsic Antiferromagnetic Spin Structure

https://shell.cas.usf.edu/~phanm//PMS.pdf

Giant magnetoimpedance materials: Fundamentals and applications

Combined rejected and naturally available heat constitute an enormous energy resource that remains mostly untapped. Thermal energy harvesting can provide a cost-effective and reliable way to convert available heat into mechanical motion or electricity. This extensive review analyzes the literature covering broad topical areas under solid-state low temperature thermal energy harvesting. These topics include thermoelectricity, pyroelectricity, thermomagneticity, and thermoelasticity. For each topical area, a detailed discussion is provided comprising of basic physics, working principle, performance characteristics, state-of-the-art materials, and current generation devices. Technical advancements reported in the literature are utilized to analyze the performance, identify the challenges, and provide guidance for material and mechanism selection. The review provides a detailed analysis of advantages and disadvantages of each energy harvesting mechanism, which will provide guidance towards designing a hybrid thermal energy harvester that can overcome various limitations of the individual mechanism.

A Review on low-grade thermal energy harvesting: Materials, methods and devices

La 1− x Pb x MnO 3 ( x =0.1, 0.2, 0.3, 0.4, and 0.5) perovskites were prepared by a solid-state reaction. Except for x =0.5 (cubic) and x =0.4 (rhombohedral), the structure of the other compositions was pseudo-rhombohedral with P1 symmetry. The particle size of the grains is depending on the Pb content of the samples. The Curie temperature T c increases from 235 K for x =0.1–310 K for x =0.2 and is almost constant (about 360 K) for x ⩾0.3. The field-cooled and zero-field-cooled thermomagnetic curves measured at low field show a split below a so-called irreversibility temperature T r , which is somewhat smaller than T c except for x =0.1, where it is 270 K. From a series of magnetic isotherms the magnetic entropy changes Δ S ( T ) were determined for a field step of 500 Oe. The maximum value of Δ S max increases with increasing x till x =0.3 and then decreases with further increasing x . The conductivity of perovskites is metallic at low temperatures and semiconducting at high temperatures. Magnetoresistance measurements have been performed.

/pdf/structure-magnetic-magnetocaloric-and-magnetoresistance-2a293u6jsb.pdf

Structure, magnetic, magnetocaloric and magnetoresistance properties of La1−xPbxMnO3 perovskite

Structural, magnetic, magnetocaloric and magnetoresistance (MR) studies on La0.7Sr0.3Mn0.95Cu0.05O3 (No. 1) and La0.7Sr0.3Mn0.9Cu0.1O3 (No. 2) perovskites are reported. The crystal structure of the samples is rhombohedral with a change of the lattice constants depending on the Cu content. FC and ZFC thermomagnetic measurements for both compositions at low field indicate that a spin–glass-like state (or cluster glass) occurs at low temperatures and a very sharp change of magnetization around the phase-transition point. The Curie temperature, TC, does almost not depend on the content of Cu substitution. A maximum magnetic-entropy change, ΔSmax, of 1.96 and 2.07 J/kg K at 13.5 kOe and 350 K is observed for sample No. 1 and No. 2, respectively. Therefore, they can be considered as active magnetic refrigerant materials for room-temperature applications. Electrical-resistance measurements show that both samples are metallic conductor for T TC; moreover, the MR is maximal around TC.

Influence of Cu substitution for Mn on the structure, magnetic, magnetocaloric and magnetoresistance properties of La0.7Sr0.3MnO3 perovskites

A thorough study of the magnetocaloric effect (MCE) in a colossal magnetoresistive compound of La0.7Sr0.3Mn0.98Ni0.02O3 has been made. The large magnetic entropy change of 7.65 J∕kg K upon an applied field of 70 kOe has been found to occur at 350 K, which allows magnetic refrigeration at room temperature. It is interesting to note that, even in high magnetic fields, the magnetic entropy change versus temperature distribution is much more uniform than that of gadolinium and several polycrystalline perovskite manganites, which is desirable for an Ericson-cycle magnetic refrigerator. It is found that such a small amount (∼2%) of substitution of Mn3+ by a magnetic ion (Ni3+ or Co3+) in the perovskite manganite can favor the spin order and hence the MCE. Undoubtedly, this observation opens a window to explore the active magnetic refrigeration at high temperatures.

Large magnetic entropy change above 300 K in a colossal magnetoresistive material La0.7Sr0.3Mn0.98Ni0.02O3

Large magnetic entropy change in Cu-doped manganites

We present the results of an investigation on the magnetocaloric effect in the perovskites of La{sub 0.845}Sr{sub 0.155}Mn{sub 1-x}M{sub x}O{sub 3} (M = Mn, Cu, Co). It is found that there was a large magnetic entropy change, i.e. a large magneto-caloric effect, in all these samples. Among them, the magnetic entropy change reaches a maximum value of 2.67 J/kg K at the applied field of 13.5 kOe for the Cu-doped sample, suggesting that this material would be a suitable candidate for the advanced magnetic refrigeration technology. The large magnetic entropy change produced by the abrupt reduction of magnetization is attributed to the strong coupling between spin and lattice that occurs in the vicinity of the ferromagnetic-paramagnetic transition temperature (T{sub C}) - which is experimentally verified by electron paramagnetic resonance study. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Nguyen Duc Tho

Papers

Structure, magnetic, magnetocaloric and magnetoresistance properties of La1−xPbxMnO3 perovskite

Influence of Cu substitution for Mn on the structure, magnetic, magnetocaloric and magnetoresistance properties of La0.7Sr0.3MnO3 perovskites

Large magnetic entropy change above 300 K in a colossal magnetoresistive material La0.7Sr0.3Mn0.98Ni0.02O3

Large magnetic entropy change in Cu-doped manganites

Large magnetocaloric effect in La0.845Sr0.155Mn1−xMxO3 (M = Mn, Cu, Co) perovskites