Magnetic field dependence of the maximum magnetic entropy change
| Title | Magnetic field dependence of the maximum magnetic entropy change |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Authors | Lyubina J, Kuz'min MD, Nenkov K, Gutfleisch O, Richter M, Schlagel DL, Lograsso TA, Gschneidner KA |
| Journal Title | Physical Review B |
| Volume | 83 |
| Pages | 012403 |
| Date Published | 01 |
| Type of Article | Article |
| ISBN Number | 1098-0121 |
| Accession Number | ISI:000286740800001 |
| Keywords | 2nd-order phase-transition |
| Abstract | The maximum isothermal entropy change in a magnetic refrigerant with a second-order phase transition is shown to depend on applied magnetic field H as follows: (-Delta S)(max) = A(H + H-0)(2/3)-AH(0)(2/3) + BH4/3. Here A and B are intrinsic parameters of the cooling material and H-0 is an extrinsic parameter determined by the purity and homogeneity of the sample. This theoretical prediction is confirmed by measurements on variously pure poly- and single-crystalline samples of Gd. The Curie point of pure Gd is found to be 295(1) K; however, the maximum of -Delta S-M is attained at a lower temperature: The higher the quality of the sample, the closer the peak position to 295 K. Further tests are reported for a series of melt-spun LaFe13-xSix alloys. These are found to follow the same field dependence, despite the fact that for certain compositions (x < 1.8) they experience a phase transition of first, rather than second, order. |
| URL | <Go to ISI>://000286740800001 |
| DOI | 10.1103/PhysRevB.83.012403 |
| Alternate Journal | Phys. Rev. B |
