Hosta

by | Mar 16, 2018 | Hosta

How Can We Help?
You are here:
< Back

Europium(II) titanate is a black mixed oxide of europium and titanium, with the chemical formula of EuTiO3. It crystallizes in the perovskite structure.[1]

History

EuTiO3 was first examined in 1966 by McGuire, Shafer, Joenk, Halperin and Pickart where the magnetic structure was examined.[2] This compound received more attention at the beginning of the 21st century (2001 to 2015) due to the low-temperature phase transition to antiferromagnetic behavior at TN = 5.5 K, which has a significant influence on the dielectric constant.[3][4][5]

Preparation

Dried Eu2O3 and Ti2O3 are mixed 1:1 and reacted in an argon atmosphere at 1400 °C:[3]

The europium is reduced and the titanium is oxidized.

Properties

Europium(II) titanate has two different crystal forms depending on the temperature. The phase transition occurs at 282 K.[3][6] The low temperature form crystallizes in the tetragonal space group I4/mcm (space group No. 140) with the lattice parameters a = 551.92(2) pm, c = 781.64(8) pm (measured at 90 K). The higher temperature form has a cubic form with Pm3m (space group No. 221) with lattice parameter a = 390.82(2) pm (measured at 300 K).[3][7] The transition temperature of the crystal structure from the low-temperature to the high-temperature phase increases with increasing pressure.[8] The compound becomes G-type antiferromagnetic below 5.5 K.[9] The specific heat capacity is 125 J·mol−1·K−1 (at 600 K).[1] 125 J·mol−1·K−1290 K is 7,6 W·m−1·K−1 and the electrical conductivity is 105 (Ω·m)−1(at 330 K).[1]

References

  1. ^ a b c 1. Muta, Hiroaki (2005). "Thermoelectric Properties of Lanthanum-Doped Europium Titanate". Materials Transactions. 46 (7): 1466–1469. doi:10.2320/matertrans.46.1466.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  2. ^ T. R. McGuire, M. W. Shafer, R. J. Joenk, H. A. Halperin, and S. J. Pickart (1966). "Magnetic structure of EuTiO3". Journal of Applied Physics. 37 (3): 981. Bibcode:1966JAP....37..981M. doi:10.1063/1.1708549.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. ^ a b c d J. Köhler, R. Dinnebier, A. Bussmann-Holder (2012). "Structural instability of EuTiO3 from X-ray powder diffraction". Phase Transitions. 85 (11): 949–955. arXiv:1205.5374. Bibcode:2012PhaTr..85..949K. doi:10.1080/01411594.2012.709634. S2CID 94709465.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ S. Kamba, D. Nuzhnyy, P. Vaněk, M. Savinov, K. Knížek, Z. Shen, E. Šantavá, K. Maca, M. Sadowski, J. Petzelt (2007). "Magnetodielectric effect and optic soft mode behaviour in quantum paraelectric EuTiO3 ceramics". Europhysics Letters. 80 (2): 27002. arXiv:0706.1882. Bibcode:2007EL.....8027002K. doi:10.1209/0295-5075/80/27002. S2CID 13856279.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ T. Katsufuji and H. Takagi (2001). "Coupling between magnetism and dielectric properties in quantum paraelectric EuTiO3". Physical Review B. 64 (5): 054415-1–054415-4. Bibcode:2001PhRvB..64e4415K. doi:10.1103/PhysRevB.64.054415.
  6. ^ Bussmann-Holder, J. Köhler, R. K. Kremer, J. M. Law (2011). "Relation between structural instabilities in EuTiO3 and SrTiO3". Physical Review B. 83 (21): 212102. arXiv:1105.6029. Bibcode:2011PhRvB..83u2102B. doi:10.1103/PhysRevB.83.212102. S2CID 118638434.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ A. Bussmann-Holder, Z. Guguchia, J. Köhler, H. Keller, A. Shengelaya, A. R. Bishop (2012). "Hybrid paramagnon phonon modes at elevated temperatures in EuTiO3". New Journal of Physics. 14 (9): 093013. arXiv:1205.6287. Bibcode:2012NJPh...14i3013B. doi:10.1088/1367-2630/14/9/093013. S2CID 118479381.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ P. Parisiades, E. Liarokapis, J. Köhler, A. Bussmann-Holder, M. Mezouar (2015). "Pressure-temperature phase diagram of multiferroic EuTiO3". Physical Review B. 92 (6): 064102. arXiv:1505.05049. Bibcode:2015PhRvB..92f4102P. doi:10.1103/PhysRevB.92.064102. S2CID 118250289.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ Z. Guguchia, H. Keller, A. Bussmann-Holder, J. Köhler, R. K. Kremer (2013). "The low temperature magnetic phase diagram of EuxSr1−xTiO3". European Physical Journal B. 86 (10): 409–412. Bibcode:2013EPJB...86..409G. doi:10.1140/epjb/e2013-40632-y. S2CID 123512501.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Categories
Table of Contents