Critical exponents of the second-order manganite Nd_0.5Sr_0.25Ca_0.25MnO₃ determined from magnetic entropy change measurements

Abstract

The critical exponents of second-order phase transition were deduced from magnetic entropy change. Using the magnetic field dependence of entropy change and the Widom scaling relation, some relevant critical exponents can be calculated directly from them. Based on critical exponents, a corresponding Arrott plot can be established as an initial model. Through a limited nonlinear fitting, we can obtain the final critical exponents. This method eliminates the drawbacks of the routine method which relies on the subjective selection of an initial model and involves the multi-step nonlinear fitting process. It was applied to the manganite NdSrCaMnO to verify its utility and feasibility. The spontaneous magnetization obtained using the final critical exponents is consistent with that deduced from the isothermal magnetization measurements, indicating that the utilization of the magnetic field dependence of magnetic entropy change to determine critical exponents is a valid method.

Keywords:

• critical exponents
• phase transitions
• magnetocaloric effect
• manganites

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Corrigendum

Acknowledgements

J. Fan would like to thank Dr Dong Chen for valuable discussion.

Additional information

Funding

This work was supported by the NUAA Fundamental Research Funding [grant number NS2013079]; the National Nature Science Foundation of China [grant number 11004196], [grant number 11204131], [grant number 11204270], [grant number U1332140].