Effects of uniaxial stress on thulium vanadate and thulium arsenate

Battison, J E; Kasten, A.; Leask, M. J. M.; Lowry, J B; Maxwell, K.J.

doi:10.1088/0022-3719/9/7/027

Cited by 13 publications

(6 citation statements)

References 12 publications

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“…At room temperature the site symmetry at the thulium ion is D2d, and the Tm3+ ion, 4f12, 3H6, should be subject to a ligand field of tetragonal symmetry. This is confirmed by Raman spectroscopy (Harley 1972), and by optical spectroscopic measurements of Laugsch (1974) and Battison al. (1976).…”

Section: T He Tm3+ Ion In Tmas04mentioning

confidence: 57%

“…For, subject to the constraint gz = 8.8, variatio of the wavefunctions for the doublet and the adjacent singlet in such a way as to maximize the value of a5 shows that it cannot exceed 3.36. This difficulty is essen tially the same as that pointed out byBattison et (1976) concerning the in terpretation byBecker (1976) of his optical double refraction measurements in a perpendicular magnetic field. In fact his value of gx (which should be gy with our choice of axes) is equivalent to a value of a5 = {gx/2gj) = 4.47, even larger than that required by our n.m.r.…”

mentioning

confidence: 55%

“…Single crystals of TmAs04 have been studied previously by optical spectroscopy in this laboratory (Battison et al 1976) and the same apparatus was used for a new measurement of the Zeeman effect. Light from a 2.5 kW xenon lamp was focused onto a single crystal in the glass tail of a cryostat that could be filled with liquid hydrogen or liquid helium.…”

Section: Optica L Spe C T R U Mmentioning

confidence: 99%

“…Next we use the mean field relation (7), with a small correction for the effect of the thermal population at TD of the low lying singlet at energy Becker (1976 Optical and magnetic studies of TmAs04 The measurements of Becker extended into fields of 2 T, and it was decided to make a more direct test by observing the variation of the two lowest energy levels in fields up to 8 T, by using optical absorption spectroscopy. Measurements were made with the field at a number of angles in the (001) plane, but for simplicity we show in figure 6 only those with B along a principal axis [110], at T = 4.2 K. In such large fields the magnetic Zeeman interaction causes the order parameter (/S'2) to diminish through the admixture of the low-lying singlet into the ground doublet (see the equations in §2 of Becker (1976)). A computer program was used to cal culate the energy levels, and the fit is also shown in figure 6.…”

Section: The Value Of A0mentioning

confidence: 99%

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Optical and magnetic studies of TmAsO ₄

Bleaney

Gregg

Leask

et al. 1984

Proc. R. Soc. Lond. A

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In the tetragonal paramagnet thulium arsenate, TmAsO 4 , the lowest manifold of the Tm 3+ ion, 4f 12 , 3 H 6 is split by the crystal field, which leaves a ground doublet with a nearby singlet at 13.8 cm -1 . Below a critical temperature T D = 6.13(3) K, a cooperative Jahn-Teller distortion splits the ground doublet, which produces domains with principal axes [110], [11̄0]. The behaviour of the three lowest levels has been studied by using high resolution optical absorption spectroscopy with magnetic fields up to 9 T along the [001] axis and in the (001) plane. Enhanced nuclear magnetic resonance of the single stable isotope 169 Tm has also been observed in these directions. Parallel to the c -axis the results confirm that from 1.6 to 4.2 K the magnitude of the Jahn-Teller splitting follows mean field theory to within 0.2 %. New values of the parameters give good agreement with mean field theory, but in the (001) plane the n. m. r. and optical measurements disagree with each other and with calculations based on the crystal field parameters of Bingham et al . (1984), which indicates that other interactions may be present.

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Section: T He Tm3+ Ion In Tmas04mentioning

confidence: 57%

mentioning

confidence: 55%

Section: Optica L Spe C T R U Mmentioning

confidence: 99%

Section: The Value Of A0mentioning

confidence: 99%

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Optical and magnetic studies of TmAsO ₄

Bleaney

Gregg

Leask

et al. 1984

Proc. R. Soc. Lond. A

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“…I n a simple Debye model the ratio AT^/^^^ should be -1/3 [22], experiments yield ratios between -1/3 [24] and zero [22]. Mainly for simplicity and t o avoid too many adjustable parameters, we shall assumeATm = 0 in the following.…”

Section: Tmas04 and Tmvo4mentioning

confidence: 99%

Specific Heat Experiments at the Cooperative Jahn‐Teller Transition in the Mixed Crystal Systems (Tb_x, Tm_1−x)AsO₄ and (Tb_x, Tm_1−x)VO₄

Kasten

Kahle

Klöfer

et al. 1987

Physica Status Solidi (b)

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sIEBERT4) Dedicated to Prof. Dr. A. SEEQER on the occasion of his 60th birthday Single crystals of the systems (Tb,, Tml-,)AsO, and (Tb,, Tml-,)VO, are investigated by means of specific heat measurements in the temperature region 1 to 40 K. Whereas for the arsenate a cooperative Jahn-Teller distortion is observed over the whole concentration range x, in the vanadate the phase transition is missing for 0.1 5 x 0.4. This can be understood in mean field theory taking into account the effect of local strains which are assumed to have a random (Gaussian) distribution. Einkristalle der Systeme (Tb,, Tml -,)AsOl und (Tb,, Tml-,)VO, werden mit Hilfe von Spezifische-Warme-Messungen im Temperaturbereich 1 bis 40 K untersucht. Wkhrend fur das Arsenat bei allen Konzentrationen x eine kooperative Jahn-Teller-Verzerrung beobachtet wird, fehlt im Vanadat der Phasenubergang fur 0,l 5 x 5 0,5. Dies kann im Rahmen einer Molekularfeldtheorie verstanden werden, wenn man den EinfluB lokaler Vorverzerrungen berucksichtigt, deren Verteilung statistisch (Gaul3sch) angenommen wird. l ) Engesserstr. 7, POB 6980, D-7500 Karlsruhe 1, FRG.

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