Field dependence of the magnetocaloric effect in Gd and (Er 1−x Dy x )Al 2 : Does a universal curve exist?

We report the magnetocaloric effect (MCE) in a Pr0.52Sr0.48MnO3 single crystal. A peak in the temperature dependence of magnetic entropy change (ΔSM) with a fairly large negative value (≈3.8 J/kg K) is observed at 275 K close to Curie temperature. MCE is spread over a wide temperature range resulting in a considerable refrigerant capacity (≈293 J/kg). At low temperature the sign of ΔSM changes, below which anomalous field dependence of ΔSM is observed indicating the coexistence of ferromagnetic and antiferromagnetic interactions. Interplay between the interactions is strongly influenced by direction and magnitude of applied magnetic field in the ordered state.

mentioning

confidence: 99%

Anomalous magnetic field dependence of magnetocaloric effect at low temperature in Pr0.52Sr0.48MnO3 single crystal

Patra

Majumdar

Giri

et al. 2010

“…It has been demonstrated that it can be successfully applied to different families of soft magnetic amorphous alloys 1,2 ͑for which it was initially developed͒ and subsequently extended to rare earth based crystalline materials. [3][4][5] The theoretical background for this universal curve construction lies on scaling laws. 6 More recently, it has been shown 7,8 that the same phenomenological procedure is suitable for scaling the adiabatic temperature change, ⌬T ad , of second order phase transition materials.…”

Section: Introductionmentioning

confidence: 99%

Field dependence of the adiabatic temperature change in second order phase transition materials: Application to Gd

Franco

Conde

Romero-Enrique

et al. 2009

Articles you may be interested inComparison of the order of magnetic phase transitions in several magnetocaloric materials using the rescaled universal curve, Banerjee and mean field theory criteria J. Appl. Phys. 117, 17D144 (2015) The field dependence of the adiabatic temperature change ⌬T ad of second order phase transition materials is studied, both theoretically and experimentally. Using scaling laws, it is demonstrated that, at the Curie temperature, the field dependence of ⌬T ad is characterized by H 1/⌬ . Therefore, as the magnetic entropy change ⌬S M follows a H ͑1−␣͒/⌬ power law, these two dependencies coincide only in the case of a mean field model. A phenomenological construction of a universal curve for ⌬T ad is presented, and its theoretical justification is also given. This universal curve can be used to predict the response of materials in different conditions not available in the laboratory ͑extrapolations in field or temperature͒, for enhancing the resolution of the data and as a simple screening procedure for the characterization of materials.

“…15,23 It has been recently demonstrated that the ⌬S M curves measured with different maximum applied fields collapse into a single master curve when properly rescaled. [21][22][23] This phenomenological master curve is obtained by plotting the normalized ⌬S M ͑T͒ curves versus a temperature axis which is rescaled in a different way below and above T C . This rescaling is made by imposing that the position of two additional reference points in the curve corresponding to = ±1…”

Section: Resultsmentioning

confidence: 99%

“…This simplicity allowed us to develop a master curve for the field dependence of the magnetic entropy change, 21 which has been extended to lanthanide-based alloys. 22 Under some circumstances ͑namely, alloy series with similar values of the critical exponents͒, this master curve can also be extended to series of alloys with different compositions, being a powerful tool for making reasonable extrapolations to field and/or temperatures outside the available experimental range in some laboratories. 18,23 Up to date, there is no published information about the magnetocaloric effect in Hitperm-type alloys, which constitute one of the well-known families of nanocrystalline alloys coming from amorphous precursors.…”

Section: Introductionmentioning

confidence: 99%

Magnetocaloric effect in Mn-containing Hitperm-type alloys

Franco

Conde

Blázquez

et al. 2007

Articles you may be interested inInfluence of microstructure on the enhancement of soft magnetic character and the induced anisotropy of field annealed HITPERM-type alloys J. Appl. Phys. 117, 17A301 (2015) The magnetocaloric effect of Fe 60−x Mn x Co 18 Nb 6 B 16 ͑x =0,2,4͒ is studied. Mn addition decreases the Curie temperature of the alloys but also reduces the peak entropy change and the refrigerant capacity of the material. The estimated adiabatic temperature change, for a maximum applied field of 15 kOe, is 1.3 K. Obtained values are comparable to those of some Nanoperm-type alloys. The magnetic entropy change, ⌬S M , of the studied samples follows a master curve, which is the same for all of them. The exponent controlling the field dependence of ⌬S M scales with reduced temperature in the same way as the master curve does.