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Comparing magnetism in isostructural oxides A[sub](0.8)La[sub](1.2)MnO[sub](4.1) : anisotropic spin glass (A = Ba) versus long range order (A = Sr)
Mirela Dragomir, Paul A. Dube, Iztok Arčon, Chad Boyer, Meghan Rutherford, Christopher Wiebe, Graham King, Hanna Dabkowska, John E. Greedan, 2019, original scientific article

Abstract: This study presents the strikingly distinct magnetic properties of two isostructural compounds, Ba0.8La1.2MnO4.1 and Sr0.8La1.2MnO4.1 (K2NiF4 type, I4/mmm). Spectroscopic studies have shown that Mn is in a +3.0(1) oxidation state only, in both compounds; therefore, the charge is balanced by accommodating extra oxygen at interstitial sites, as confirmed by neutron powder diffraction. We found that the Ba compound exhibits an exceedingly rare anisotropic spin glass behavior, Tg = 26.4(4) K, with the moment freezing along the c-axis only while the in-plane spin components remain dynamic well below Tg. Experimental results including neutron diffraction, heat capacity, and magnetic (dc and ac) measurements performed on an oriented single crystal support this conclusion. This is a remarkable result, the only other known example of an anisotropic spin glass being Fe2TiO5. The spin glass state in Ba0.8La1.2MnO4.1 is argued to arise due to competing antiferromagnetic and ferromagnetic 180° Mn3+−O−Mn3+ superexchange interactions. In contrast, the Sr analogue shows 2D antiferromagnetic correlations and long-range antiferromagnetic order below 95(1) K with a remarkably reduced ordered moment of 1.449(49) μB/Mn3+ instead of the ∼4 μB expected for an S = 2 ion.
Keywords: antiferomagnetiki, Mn XANES, struktura
Published in RUNG: 23.10.2019; Views: 3394; Downloads: 0
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Room-Temperature Synthesis and Optical Properties of NdVO4 Nanoneedles
Matjaž Valant, Mirela Dragomir, 2018, original scientific article

Keywords: nanostruukture, kemijska sinteza, optične lastnosti
Published in RUNG: 01.10.2018; Views: 4750; Downloads: 0
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A facile chemical method for the synthesis of 3C–SiC nanoflakes
Mirela Dragomir, Matjaž Valant, Mattia Fanetti, Yurij Mozharivskyj, 2016, original scientific article

Keywords: SiC, flakes, nano-flakes, chemical synthesis
Published in RUNG: 04.03.2016; Views: 5254; Downloads: 0
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