Investigations of the effect of nonmagnetic Ca substitution for magnetic Dy on spin-freezing in Dy2Ti2O7

Physical properties of partially Ca substituted hole-doped Dy2Ti2O7 have been investigated by ac magnetic susceptibility \chi_ac(T), dc magnetic susceptibility \chi(T), isothermal magnetization M(H) and heat capacity C_p(T) measurements on Dy1.8Ca0.2Ti2O7. The spin-ice system Dy2Ti2O7 exhibits a spin-glass type freezing behavior near 16 K. Our frequency dependent \chi_ac(T) data of Dy1.8Ca0.2Ti2O7 show that the spin-freezing behavior is significantly influenced by Ca substitution. The effect of partial nonmagnetic Ca2+ substitution for magnetic Dy3+ is similar to the previous study on nonmagnetic isovalent Y3+ substituted Dy2-xYxTi2O7 (for low levels of dilution), however the suppression of spin-freezing behavior is substantially stronger for Ca than Y. The Cole-Cole plot analysis reveals semicircular character and a single relaxation mode in Dy1.8Ca0.2Ti2O7 as for Dy2Ti2O7. No noticeable change in the insulating behavior of Dy2Ti2O7 results from the holes produced by 10% Ca2+ substitution for Dy3+ ions.Comment: 9 pages, 7 figures, 1 tabl

A Novel Longitudinal Mode in the Coupled Quantum Chain Compound KCuF3

Inelastic neutron scattering measurements are reported that show a new longitudinal mode in the antiferromagnetically ordered phase of the spin-1/2 quasi-one-dimensional antiferromagnet KCuF3. This mode signals the cross-over from one-dimensional to three-dimensional behavior and indicates a reduction in the ordered spin moment of a spin-1/2 antiferromagnet. The measurements are compared with recent quantum field theory results and are found to be in excellent agreement. A feature of the data not predicted by theory is a damping of the mode by decay processes to the transverse spin-wave branches.Comment: 9 pages of text plus 4 postscript figures (1 color

Progress and data February 1973

This report summarizes progress and data available for the following investigations. Lupin Growth Analysis, Rape Growth Analysis, Fallow Re-assessment, 72M29 Wheat Variety - Root Growth Study

Fallow re-assessment (Merredin Research Station)

Fallow Re-assessment - (Merredin Research Station) - 72M29. Table 1: Growing season rainfall and yields at Merredin

Influence of planting systems on crop growth and soil water relations.

Summary of experimental results 1981. Influence of planting systems on crop growth and soil water relations. Rainfall infiltration, drainage and water use. Yields. The two late sown treatments of previous years were replaced in 1981 with deep ripping treatments. Details are presented in R. Jarvis\u27 report. 77A16, 77WH17

1975 Fallow re-assessment and soil physical data accumulation

This report summarises progress and data available for the following investigations. 1. Fallow Re-assessment - 72M29. 2. Soil Physical Data Accumulation. (a) Evaluation of methods of bulk density measurement. (b) Water holding capacities and mechanical analyses of wheatbelt soils. (c) Water holding capacities of metropolitan sands. TABLE 3 Water holding capacities (1/10 - 15 Atmosphere water contents) of metropolitan sands (mm of water). Bulk density of 1.6 assumed. 1. Medina Research Station. 2. Morley White Sand. 3. Karrakatta Sand. 4. Bassendean Sand. 5. South Perth Lawn. 6. South Perth Scrub. 7. Underwood Avenue Research Station. 8. Floreat Park Sand. 9. Tuart Sand. Highest values were obtained at the Medina and Underwood Avenue Research stations. Generalised recommendations can be aimed at the 15 to 22 mm range of water storage to 60 cm depths. Water storage to 60 cm soil depth can be as low as 10mm

Sowing systems, effect on mineralisation of soil nitrogen and fallow re-assessment.

Planting systems investigation. Avondale, Esperance, Wongan Hills, Mt. Barker, Merrden research stations. Fallow re-assessment, 72M29

Fallow re-assessment - Wheat variety investigations- root growth and moisture use

This report summarises progress and data available for the following investigations - Fallow Re-assessment - 72M29. Wheat Variety Investigations - Root Growth and Moisture Use. Location: Wongan Hills Research Station. Merredin Research Station