Exchange optics in Gd-doped EuO

Schoenes, J.; Wächter, P.

doi:10.1103/physrevb.9.3097

Cited by 157 publications

(86 citation statements)

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“…Also to be noted is that the antiferromagnetic coupling discussed in this paper provides a satisfactory explanation for the apparent contradiction that electron doping increases Tc and, at the same time, reduces the red shift in the optical absorption, which implies a decrease in the ferromagnetic 11 coupling. 47,48 We have focused on magnetic polarons here. Models based on exchange splitting of the conduction electrons have difficulty in producing the antiferromagnetic coupling and may require rare earth doping to achieve Tc > 69 K. 29,49 The magnetic polaron model can also explain why most oxygen deficient …”

Section: Resultsmentioning

confidence: 99%

Antiferromagnetic coupling in EuO1−x

2012

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The mechanism for the ferromagnetic order in oxygen-deficient europium monoxide EuO 1-x at temperatures higher than 69 K (the Curie temperature Tc of stoichiometric EuO) remains controversial. We have investigated the magnetization of EuO 1-x thin films prepared via pulsed laser deposition as a function of temperature and applied field. The ferromagnetic ordering above 69 K originates from the exchange coupling between the doped electrons and Eu 4f moments and is described using a magnetic polaron model. Our data show that the magnetic polarons are coupled antiferromagnetically to the Eu 4f local moments that dominate the magnetization below 69 K. The magnetic polaron state is stable below 69 K and seems to persist down to a relatively low temperature. An explanation is given to account for the antiferromagnetic coupling. We also describe the evolution of the phases of the magnetic orders as the temperature is varied in EuO 1-x .2

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Section: Resultsmentioning

confidence: 99%

Antiferromagnetic coupling in EuO1−x

2012

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“…The temperature at which these materials show the largest Faraday rotation can possibly be increased by doping with Gd. For example, alloying EuO with Gd can raise the Curie temperature from 69 K to 135 K. 65,66 EuSe and EuS combine large magneto-optical response, high saturation magnetic flux density, and simple thin-film fabrication via physical vapor deposition. Thus, they are promising materials for further magneto-plasmonic studies with structures that are not restricted to designs including strictly continuous magnetooptical films, as required for true 3D structures.…”

Section: Discussionmentioning

confidence: 99%

Tunable and switchable polarization rotation with non-reciprocal plasmonic thin films at designated wavelengths

et al. 2015

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We experimentally demonstrate an ultra-thin plasmonic optical rotator in the visible regime that induces a polarization rotation that is continuously tunable and switchable by an external magnetic field. The rotator is a magneto-plasmonic hybrid structure consisting of a magneto-optical EuSe slab and a one-dimensional plasmonic gold grating. At low temperatures, EuSe possesses a large Verdet constant and exhibits Faraday rotation, which does not saturate over a regime of several Tesla. By combining these properties with plasmonic Faraday rotation enhancement, a large tuning range of the polarization rotation of up to 8.46 for a film thickness of 220 nm is achieved. Furthermore, through experiments and simulations, we demonstrate that the unique dispersion properties of the structure enable us to tailor the wavelengths of the tunable polarization rotation to arbitrary spectral positions within the transparency window of the magneto-optical slab. The demonstrated concept might lead to important, highly integrated, non-reciprocal, photonic devices for light modulation, optical isolation, and magnetic field optical sensing. The simple fabrication of EuSe nanostructures by physical vapor deposition opens the way for many potentially interesting magneto-plasmonic systems and three-dimensional magneto-optical metamaterials.

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“…At T = 20 K ∆E g shift EuO reaches value ∆E g = 0.25 eV. In an external magnetic field in terms of increasing crystal magnetization this shift increases by almost 10% [7]. From the known to date, the list of magnetic semiconductors match the magnitude of the red shift of the optical absorption edge with the above data can, again, only the crystalline phase based on manganese lanthanide in which ΔE g value can reach to different levels of doping with 0.16 to 0.2 eV [8,9].…”

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confidence: 96%

“…The second model assumes a triplet spin state of electrons O-vacancy at the same temperatures. It is their condition capable of causing local polarization already disordered spin 4f 7 electrons of europium to form domains (or clusters) that retain the short-range magnetic order. Consequently, the latest model better matches the observed magnetic and thermodynamic experimental data [16].…”

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confidence: 99%

“…With decreasing temperature, the mobility of carriers in crystals EuO increases almost an order of magnitude, and at T = 4,2 K, it reaches the value of u = (2 -4)·10 2 cm 2 /(V · s). Its monoxide in the magnetic phase transition area (Curie temperature, MPT) is peculiar and large negative magnetoresistance effect, (p o -ρ H )/p o , reaching around the value of 10 6 for the crystals with the nondegenerate electric conductivity [7].…”

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To The Theory of Inverse Transition Insulator-Metal Anion Defective Ferromagnetic Semiconductor Euo<sub>1- δ</sub>

Borukhivich¹,

Troshin²

2017

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Abstract. Based on the available experimental data are made model estimates and the implementation criteria of inverse electron transition insulator-metal set in the "classical" ferromagnetic semiconductor -europium monoxide which is the base model of research in semiconductor spintronics.Keywords: Ferromagnetic semiconductor, europium monoxide, insulator-metal transition, nonstoichiometry, local electronic level, magnetic polaronIn connection with the continued works in recent years the rapid development in the physical materials field of semiconductor spin electronics (spintronics) as a model of research has been and remains a "classic" ferromagnetic semiconductor -europium monoxide -EuO [1]. A characteristic feature of its crystal chemistry is that it is a phase of variable composition, EuO 1+δ , which extends the boundaries of homogeneity in the area of excess (δ<0), and the lack of (δ>0) metal. True nonstehiometric area it is fairly narrow: δ -index varies between 0> δ> 0.005 (excess metal) and 0 <δ <0.035 (excess oxygen).[2] However, depending on the oxygen content significantly are changing the properties monoxide, in particular, the electrical conductivity. At the same time regardless of the sign δ it is always characterized by n-type and its temperature dependence is typical for semiconductors. The specific conductivity values of EuO phase at room temperature are in the range σ = 10 -8 -10 -12 (Ohm•cm) -1 . In the case of excess metal (i.e. anionic defects) samples EuO 1-δ -phase below the Curie temperature (T c = 69.4 K) at the T i ≈ 52 K to test the temperature insulator-metal transition (I -M) with a conductivity jump 13 -15 orders of magnitude [3,4] (Fig.1). A greater jump in the specific electrical resistivity of conductive solid phase is observed only in the superconducting transition in them. In this case, for the phase EuO 1-δ it is the second largest known today jump electrical conductivity in crystals. Moreover, it is the first of the public when it becomes metal the low-temperature ferromagnetic-ordered phase. To date, similar to the character of semiconductor-metal transition, although with a much smaller jump of electric resistivity, Δρ/ρ, is known for some compounds doped of the ferromagnetic ordered lanthanum manganites -the magnetic semiconductors, a value of T c which is capable of more than room temperature [5]. Since the physical nature the I -M-transition in this class of materials has a lot of similarities, we reproduce here the most adopted model previously proposed for europium monoxide and, as we see, there is no other alternative. Illustration of this transition for EuO 1-δ crystals with an index of 0 <δ<0,005 in Fig. 1 also reproduces the effects of an external magnetic field [6].It is evident that the latter shifts the temperature of the electronic transition in the direction of its increase, several reducing the magnitude of the jump ∆ρ/ρ, but without destroying the character of the transition. It should be noted that the insulator-metal transition in a defective oxygen europ...

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Exchange optics in Gd-doped EuO

Cited by 157 publications

References 20 publications

Antiferromagnetic coupling in EuO1−x

Antiferromagnetic coupling in EuO1−x

Tunable and switchable polarization rotation with non-reciprocal plasmonic thin films at designated wavelengths

To The Theory of Inverse Transition Insulator-Metal Anion Defective Ferromagnetic Semiconductor Euo<sub>1- δ</sub>

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