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TT: Fachverband Tiefe Temperaturen
TT 30: Caloric Effects in Ferromagnetic Materials (joint session MA/TT)
TT 30.6: Vortrag
Dienstag, 10. März 2026, 11:00–11:15, POT/0151
Manipulating Magnetocaloric Properties Through Magnetic Exchange at Mn3−xGaC/Fe Interfaces — •Ivan Tarasov and Ulf Wiedwald — Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
Magnetocaloric materials enable solid-state cooling by exploiting temperature changes under magnetic-field variation. Manganese-based antiperovskites (APVs, Mn3AX) are promising materials due to their sharp, tunable first-order magnetostructural transition (FOMST). A key challenge is to control the working temperature window and enhance the magnetocaloric response within a given material system. Tailoring magnetic exchange interactions offers a new strategy.
Here, we investigate APV/Fe bilayers, focusing on interface-driven exchange effects. Uncoupled Mn2GaC1.1 films show a sharp FOMST at 189 K with a strong ∂ M/∂ T peak. A 5 nm Fe cap lowers the transition to 175 K, broadens hysteresis, and suppresses the ∂ M/∂ T peak above 1 T. The bare APV exhibits Δ Sm ≈ 10 J kg−1 K−1 at B = 6 T, whereas coupling reduces this to ∼ 1 J kg−1 K−1 at B = 5 T. In multi-domain bilayers, ∂ M/∂ T increases by 15% (AFM–FM) and 46% (FM–PM) for a Fe film thickness of t = 2.6 nm, but disappears for t = 21 nm, accompanied by an anomaly near 50 K linked to interfacial AFM ordering.
Funding by the Deutsche Forschungsgemeinschaft (DFG) within CRC/TRR 270, project B02 (Project-ID 405553726) is gratefully acknowledged.
Keywords: Antiperovskite; Magnetic Exchange coupling; Magnetocaloric effect; Thin films