Magnetic proximity effect features in antiferromagnetic/ferrimagnetic core-shell nanoparticles.
A study of "inverted" core-shell, MnO/gamma-Mn(2)O(3), nanoparticles is presented. Crystal and magnetic structures and characteristic sizes have been determined by neutron diffraction for the antiferromagnetic core (MnO) and the ferrimagnetic shell (gamma-Mn(2)O(3)). Remarkably, while the MnO core is found to have a T_{N} not far from its bulk value, the magnetic order of the gamma-Mn(2)O(3) shell is stable far above T_{C}, exhibiting two characteristic temperatures, at T approximately 40 K [T_{C}(gamma-Mn(2)O(3))] and at T approximately 120 K [ approximately T_{N}(MnO)]. Magnetization measurements are consistent with these results. The stabilization of the shell moment up to T_{N} of the core can be tentatively attributed to core-shell exchange interactions, hinting at a possible magnetic proximity effect.
Golosovsky
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St. Petersburg Nuclear Physics Institute, 188300, Gatchina, St. Petersburg, Russia.
Salazar-Alvarez
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G
López-Ortega
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A
González
M A
MA
Sort
J
J
Estrader
M
M
Suriñach
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S
Baró
M D
MD
Nogués
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J