Потрійні системи Lu-V-{Ge, Sn}

The isothermal sections of the phase diagrams of the Lu–V–Ge and Lu-V-Sn ternary systems were constructed at 870 K over the whole concentration range using X-ray diffraction and EPM analyses. In the Lu-V-Ge system a formation of the substitutional solid solution Lu5Ge3-xVx based on the Lu5Ge3binary compound (Mn5Si3 structure type) was found up to 6 at. % V. Insertion of the V atoms in the structure of the LuGe2 binary germanide (ZrSi2structure type, up to 5 aт. % V) results in the formation of the LuV0,15Ge2 ternary phase (CeNiSi2 structure type, space group Cmcm, a=0.40210(4),b=1.5661(1), c=0.38876(3) nm), which corresponds to the limit composition of the interstitial solid solution LuVxGe2. The interaction between the elements in the Lu-V-Sn system results in the formation of one ternary compound LuV6Sn6 (SmMn6Sn6-type, space group P6/mmm, a=0.5503(2), c=0.9171(4) nm) at investigated temperature.Ізотермічні перерізи діаграм стану потрійних систем Lu–V–Ge і Lu-V-Sn побудовані за температури 870 K в повному концентраційному інтервалі методами рентгенофазового, рентгеноструктурного і мікроструктурного аналізів. В системі Lu-V-Ge на основі бінарної сполуки Lu5Ge3(структурний тип Mn5Si3) встановлено утворення твердого розчину заміщення Lu5Ge3-xVx до вмісту 6 aт. % V. Включення атомів V в структуру бінарного германіду LuGe2 (структурний тип ZrSi2, до вмісту 5 aт. % V) приводить до утворення тернарної фази LuV0,15Ge2 (структурний тип CeNiSi2, просторова група Cmcm, a=0,40210(4), b=1,5661(1), c=0,38876(3) нм), яка відповідає граничному складу твердого розчину включення LuVxGe2. Взаємодія компонентів у системі Lu-V-Sn за температури дослідження характеризується утворенням тернарної сполуки LuV6Sn6(структурний тип SmMn6Sn6, просторова група P6/mmm, a=0,5503(2), c=0,9171(4) нм)

Tuning a sign of magnetoelectric coupling in paramagnetic NH2(CH3)2Al1-xCrx(SO4)*6H2O crystals by metal ion substitution

Hybrid organometallic systems offer a wide range of functionalities, including magnetoelectric interactions. However, the ability to design on-demand ME coupling remains challenging despite a variety of host-guest configurations and ME phases coexistence possibilities. Here, we report the effect of metal-ion substitution on the magnetic and electric properties in the paramagnetic ferroelectric DMAAS crystals. Doing so we are able to induce and even tune a sign of the ME interactions in the paramagnetic ferroelectric state. Both studied samples with 6.5% and 20% of Cr become paramagnetic, contrary to the initial diamagnetic compound. Due to the isomorphous substitution with Cr the ferroelectric phase transition temperature increases nonlinearly, with the shift being larger for the sample with Cr content of 6.5%. A magnetic field applied along the polar c axis increases ferroelectricity for this sample and shifts Tc to higher values, while inverse effects are observed for sample containing 20% of Cr. The ME coupling coefficient of 1.7ns/m found for a crystal with 20% of Cr is among the highest reported up to now. The observed sign change of ME coupling coefficient with a small change in Cr content paves the way for ME coupling engineering.Comment: 7 pages, 6 figures. New Organometallic Magnetoelectric and Ferroelectric compoun

Потрійна система Er-Cr-Ge

The isothermal section of the phase diagram of the Er–Cr–Ge ternary system was constructed at 1070 K over the whole concentration range using X-ray diffractometry, metallography and electron microprobe (EPM) analysis. The interaction between the elements in the Er−Cr−Ge system results in the formation of two ternary compounds: ErCr6Ge6 (MgFe6Ge6-type, space group P6/mmm, Pearson symbol hP13; a = 5.15149(3), c = 8.26250(7) Ǻ; RBragg = 0.0493, RF = 0.0574) and ErCr1-хGe2 (CeNiSi2-type, space group Cmcm, Pearson symbol oS16, a = 4.10271(5), b = 15.66525(17), c = 3.99017(4) Ǻ; RBragg = 0.0473, RF = 0.0433) at investigated temperature. For the ErCr1-xGe2 compound, the homogeneity region was determined (ErCr0.28-0.38Ge2; a = 4.10271(5)-4.1418(9), b = 15.6652(1)-15.7581(4), c = 3.99017(4)-3.9291(1) Ǻ).Ізотермічний переріз діаграми стану потрійної системи Er–Cr–Ge побудований за температури 1070 K в повному концентраційному інтервалі методами рентгенофазового, рентгеноструктурного і мікроструктурного аналізів. Взаємодія компонентів у системі Er–Cr–Ge за температури дослідження характеризується утворенням двох тернарних сполук ErCr6Ge6 (структурний тип MgFe6Ge6, просторова група P6/mmm, символ Пірсона hP13; a = 5,15149(3), c = 8,26250(7) Ǻ; RBragg = 0,0493, RF = 0,0574) іErCr1-хGe2 (структурний тип CeNiSi2, просторова група Cmcm, символ Пірсона oS16, a = 4,10271(5), b = 15,6652(1), c = 3,99017(4) Ǻ; RBragg = 0,0473, RF = 0,0433). Для сполуки ErCr1-хGe2 визначена область гомогенності (ErСr0,28-0,38Ge2; a = 4,10271(5)-4,1418(9), b = 15,6652(1)-15,7581(4), c = 3,99017(4)-3,9291(1) Ǻ)

Взаємодія компонентів у потрійній системі Gd-Mn-Sn при 873 і 673 K

The interaction of the components in the Gd-Mn-Sn ternary system was studied using the methods of X-ray and microstructure analyses, in the whole concentration range. The phase diagrams of the Gd-Mn-Sn system were constructed at 873 and 673 K. At both temperature of investigation the Gd-Mn-Sn system is characterized by existence of two ternary compounds: GdMn6Sn6 (MgFe6Ge6 structure type, space group P6/mmm) and Gd4Mn4Sn7 (Zr4Co4Ge7 structure type, space group I4/mmm). The formation of the interstitial solid solution GdMnхSn2 based on GdSn2 (ZrSi2-type) binary compound was found up to 10 at. % Mn at 873 K and 673 K. The existence of the substitutional solid solution based on GdMn2 (MgCu2-type) was observed up to 5 at.% Sn and 3 at. % Sn at 873 K and 673 K, respectively.Методами рентгенофазового і мікроструктурного аналізів досліджено взаємодію компонентів у потрійній системі Gd-Mn-Sn у повному концентраційному інтервалі та побудовані діаграми фазових рівноваг за температур 873 K і 673 K. За обох температур дослідження в системi утворюються дві тернарні сполуки GdMn6Sn6(структурний тип MgFe6Ge6, просторова група P6/mmm) і Gd4Mn4Sn7 (структурний тип Zr4Co4Ge7, просторова група I4/mmm). На основi бiнарного станiду GdSn2зі структурою типу ZrSi2 встановлено існування твердого розчину включення GdMnхSn2 до вмісту 10 ат. % Mn за температур 873 K і 673 K. На основі бінарної сполуки GdMn2 (структурний тип MgCu2) утворюється твердий розчин заміщення до вмісту 5 ат. % Sn при 873 K і до вмісту 3 ат. % Sn при 673 K

Tuning a sign of magnetoelectric coupling in paramagnetic NH2(CH3)(2)Al1-xCrx(SO4)(2) x 6H(2)O crystals by metal ion substitution

Hybrid organometallic systems offer a wide range of functionalities, including magnetoelectric (ME) interactions. However, the ability to design on-demand ME coupling remains challenging despite a variety of host-guest configurations and ME phases coexistence possibilities. Here, we report the effect of metal-ion substitution on the magnetic and electric properties in the paramagnetic ferroelectric NH2(CH3)(2)Al1-xCrx(SO4)(2) x 6H(2)O. Doing so we are able to induce and even tune a sign of the ME interactions, in the paramagnetic ferroelectric (FE) state. Both studied samples with x = 0.065 and x = 0.2 become paramagnetic, contrary to the initial diamagnetic compound. Due to the isomorphous substitution with Cr the ferroelectric phase transition temperature (T-c) increases nonlinearly, with the shift being larger for the 6.5% of Cr. A magnetic field applied along the polar c axis increases ferroelectricity for the x = 0.065 sample and shifts Tc to higher values, while inverse effects are observed for x = 0.2. The ME coupling coefficient alpha(ME) = 1.7 ns/m found for a crystal with Cr content of x = 0.2 is among the highest reported up to now. The observed sign change of aME with a small change in Cr content paves the way for ME coupling engineering

Crystal structures of ErGe2 and TmGe2 compounds

Crystal structures of ErGe2 and TmGe2 compounds were determined by X-ray single crystal diffraction. Both TmGe2 and ErGe2 crystallized with the ZrSi2 structure type (space group Cmcm)

Structural Properties and Temperature Behaviour of Optical Absorption Edge in Polycrystalline ZnO:X (Cu,Ag) Films

Silver- and copper-doped ZnO lms were prepared by radio-frequency magnetron sputtering on glass substrates. The in uence of dopants content on the structural, morphological properties as well as on evolution of the optical absorption edge was considered. It has been found that Ag- and Cu-doped ZnO lms are characterized by wurtzite crystalline structure with the preferred direction of crystalline orientation (002). The sizes of grains within the lms were found to be dependent on the type of dopant. The temperature evolution of the optical absorption edge is described by the modi ed Urbach rule that re ects polycrystalline nature of the material. The corresponding parameters concerning electron (exciton ) phonon interaction, phonon energies and temperature changes of the band-gap were determined and analysed