Room temperature ferromagnetism and its correlation to ferroelectricity of manganese embedded in lead zirco-titanate

• Published in: Thin solid films Vol. 669; pp. 440 - 449
• Main Authors: Bucur, Ioana Cristina, Apostol, Nicoleta G., Abramiuc, Laura E., Tănase, Liviu C., Tache, Cristian A., Lungu, George A., Costescu, Ruxandra M., Chirilă, Cristina F., Trupină, Lucian, Pintilie, Lucian, Teodorescu, Cristian M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2019
• Subjects: Charge accumulation; Diluted magnetic semiconductors; Ferroelectrics; Indirect exchange; Magneto-optical Kerr effect; X-ray photoelectron spectroscopy; Diluted magnetic semiconductors; Ferroelectrics; Indirect exchange; Magneto-optical Kerr effect; X-ray photoelectron spectroscopy; Charge accumulation
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2018.11.018

Manganese is deposited at high temperature on (001) oriented ferroelectric lead zirco-titanate prepared in two different ways: sputter-annealed or just simply annealed in ultrahigh vacuum. Room temperature ferromagnetism (FM) is obtained for Mn deposited on sputter-annealed substrates, while for the other sample preparation a paramagnetic behaviour is obtained. Also, for the first case a clear inwards component of the polarization P(−) is observed by X-ray photoelectron spectroscopy and piezoresponse force microscopy. Composition analysis evidenced formation of Pb vacancies in the case of FM – P(−) sample, consistent with hole formation near the surface, needed both to stabilize the inwards polarization state and to intermediate ferromagnetism between Mn2+ ions. The indirect exchange ferromagnetism mediated by holes is stronger, most probably because the interaction energy is proportional with the carrier effective mass. Also, whereas in the case of unsputtered substrate a stable surface Mn oxide is formed, defect formation by sputtering seems to favor Mn migration inside the sample. This also induces the formation of a thin film where ferromagnetism and the orientation of ferroelectric polarization might have the same origin, i. e. holes accumulated near the outer surface. •Ferromagnetic ordering of Mn2+ near surfaces of ferroelectric Pb(Zr,Ti)O3(001)•Ferromagnetism intermediated by holes accumulated to compensate depolarization.•Room temperature ferromagnetism occurring on Ar+ pre-sputtered films•Ferromagnetic films exhibit a larger diffusion of Mn and inwards polarized area.•Ferromagnetism due to holes with larger effective mass