Optical absorption of octahedral ions Fe2+, Fe4+ and photoinduced effect in YIG single crystals

First principles calculation on the magnetic, optical properties and oxygen vacancy effect of CexY3−xFe5O12

“…These two additional absorption bands would increase the optical loss of the material, which was observed in the previous experimental studies of Fe 2þ rich YIG materials. 18,36,37 Another cation that the oxygen vacancies may influence is the Ce 3þ ion. Recently, it was found that Ce 3þ would change to Ce 4þ at room temperature due to its larger ionic radius compared to Y 3þ .…”

Saturation, Allowed Transitions and Quantum Interference in Laser Cooling of Solids

“…Using solely the value of the cross-section given above, the absorption saturation intensity of Fe 3+ is estimated to be 20% lower than that of Yb 3+ at 1000 nm, which is in quite good agreement with the experimental background saturation intensity reported here (albeit in a different material). For iron in other valence states, such as Fe 2+ or Fe 4+ ions, the transition near 1000 nm is allowed [43]. This would lead to a short-lived excited state and a much higher saturation intensity compared with Fe 3+ .…”

Магнетосопротивление и ИК-спектр примесных состояний в пленке Ce-=SUB=-3-=/SUB=-Fe-=SUB=-5-=/SUB=-O-=SUB=-12-=/SUB=-

“…Одна линия на частоте ω 1 исчезает при 275 K, другая на частоте ω 2 в области температур (360−400) K. Две линии перехода на длинах волн 1.95 и 2.15 µm наблюдались в Y 3 Fe 5 O 12 (YIG), легированным четырехвалентными ионами Zr[20] и Pb[21]. В работе[22] предложено объяснение, связанное с оптическими переходами в двухвалентном ионе железа в низкосимметричном кристаллическом поле. Tриплетное 5 T 2g состояние ионов Fe 2+ в октаэдре (тетраэдре) с триклинным искажением решетки расщепляется на дублет 5 E g1 и синглет A g .…”