Near room temperature magnetocaloric properties and critical behavior of binary FexCu100−xNanoparticles

• Ball milled γ-FexCu100-x nanoparticles show soft ferromagnetic properties.
• The Curie temperature of FexCu100-x nanoparticles was tuned near room temperature applications.
• The magnetocaloric properties (-ΔSm) are comparable to recently reported Fe-based alloys.
• Critical analysis of the phase transition is consistent with the 3D-Heisenberg model.
• FexCu100-x nanoparticles are potential candidates for near room temperature magnetic cooling applications.

Low cost, rare earth-free magnetocaloric materials are being intensively studied for near room temperature, energy efficient, “green”, magnetic cooling applications. We report the magnetocaloric properties and critical analysis of ball milled FexCu100-x nanoparticles for x = 30 to 35. Magnetization measurements of FexCu100-x nanoparticles show soft ferromagnetic behavior at room temperature with small coercivity (HC) values. The Curie temperature (TC) could be tuned over a wide temperature range, from 268 K to 360 K, with varying Fe content. The positive slope of the Arrott plots confirms the second order nature of the magnetic transition. Critical analysis of the magnetic phase transition using modified Arrott plots supports the 3D-Heisenberg model. The magnetocaloric effect (MCE) i.e., change in isothermal magnetic entropy (ΔSm) and relative cooling power (RCP) of FexCu100-x nanoparticles is comparable to that of other Fe based alloys. The high thermal conductivity, soft ferromagnetic behavior and magnetocaloric properties of FexCu100-x nanoparticles are potentially useful for low cost, rare earth element free magnetic cooling applications.