2,308 research outputs found
Spin Freezing in the Spin Liquid Compound FeAl2O4
Spin freezing in the -site spinel FeAlO which is a spin liquid
candidate is studied using remnant magnetization and nonlinear magnetic
susceptibility and isofield cooling and heating protocols. The remnant
magnetization behavior of FeAlO differs significantly from that of a
canonical spin glass which is also supported by analysis of the nonlinear
magnetic susceptibility term . Through the power-law analysis of
, a spin-freezing temperature, = 11.40.9~K and critical
exponent, = 1.480.59 are obtained. Cole-Cole analysis of magnetic
susceptibility shows the presence of broad spin relaxation times in
FeAlO, however, the irreversible dc susceptibility plot discourages an
interpretation based on conventional spin glass features. The magnetization
measured using the cooling-and-heating-in-unequal-fields protocol brings more
insight to the magnetic nature of this frustrated magnet and reveals
unconventional glassy behaviour. Combining our results, we arrive at the
conclusion that the present sample of FeAlO consists of a majority spin
liquid phase with "glassy" regions embedded.Comment: 5 pages, 6 figs, 2-column, Accepted to Phys. Rev.
Double-phase transition and giant positive magnetoresistance in the quasi-skutterudite GdIrSn
The magnetic, thermodynamic and electrical/thermal transport properties of
the caged-structure quasi-skutterudite GdIrSn are
re-investigated. The magnetization , specific heat and the
resistivity reveal a double-phase transition -- at 10~K
and at 8.8~K -- which was not observed in the previous report on
this compound. The antiferromagnetic transition is also visible in the thermal
transport data, thereby suggesting a close connection between the electronic
and lattice degrees of freedom in this Sn-based quasi-skutterudite. The
temperature dependence of is analyzed in terms of a power-law for
resistivity pertinent to Fermi liquid picture. Giant, positive
magnetoresistance (MR) 80 is observed in GdIrSn at
2~K with the application of 9~T. The giant MR and the double magnetic
transition can be attributed to the quasi-cages and layered antiferromagnetic
structure of GdIrSn vulnerable to structural distortions and/or
dipolar or spin-reorientation effects. The giant value of MR observed in this
class of 3:4:13 type alloys, especially in a Gd-compound, is the highlight of
this work.Comment: 20 pages single column, 7 figures, 1 table; Accepted to J. Appl.
Phys., 201
Screening of in vitro derived mutants of banana against nematodes
Investigations were carried out to screen the in vitro derived mutants of banana cv. Robusta (Caveidish- AAA) and Rasthali (Silk- AAB) by using certain bio-chemical parameters including some enzyme activities. The mutants tested were Ro Im V4 6-1-1, Ro Im V4 6-1-2, Ro Im V4 6-2-1, Si Im V4 10-5-3, Si Im V4 4 6-2-5 along with respective susceptible checks (Robusta and Rasthali), tolerant check (Anaikomban- AA) and resistant check (Pisang Lilin- AA). Various biochemical assays used were total phenol, tannin content, lignin content, peroxidase, polyphenol oxidase, phenyl alanine ammonia lyase and ascorbic acid oxidase. The results revealed that the mutants namely Ro Im V4 6-1-1 and Si Im V4 10-5-3 were found to be resistant while the mutant Ro Im V4 6-2-1 was moderately resistant. The rest of the mutants namely Ro Im V4 6-1-2 and Si Im V4 6-2-5 were found to be susceptible to nematodes. The resistant and moderately resistant mutants of banana could be further used in breeding programmes as well as being recognized as potential cultivars of commerce.Key words: Banana, nematode, resistance, biochemical parameters, enzymes, screening
Dynamics of Team Teaching and Research in a Management School: Learning and Imperatives
This paper discusses the experience of team teaching to address the issues of integration of academic inputs by bringing multi-disciplinary perspective together and thereby enhance learning experience of participants. The paper delves on the process, events and outcome of team teaching by four faculty members at IIM Ahmedabad who collaborated in teaching, writing cases, and doing research for a period of more than three years. The experience has been summarized using the following dimensions: need for team-teaching, existing mechanisms and barriers, opportunities and potential, imperatives, fall-outs and challenges experienced in the process. The cohesion, trust and mutual respect are key imperatives. The other factors contributing to the success of team-teaching are strong felt need by the members for integration in programmes, complementary skills and experiences of team members, frequent programmes with integrated components that provided continuous opportunities for learning, co-location of the instructors, and off-site programmes that provided opportunities for close get-togethers. The autonomy granted by the institution to instructors and co-coordinators to design and execute learning opportunities was also instrumental in the success. In an environment where the rule of the game is individualism, forming teams creates fears of loss of importance and recognition. The experience shows that the competency of the members and the overall effectiveness of the tasks are strengthened if the team believes in “reciprocating interdependence”. This can be possible only if members allow themselves opportunities to experiment, improvise and review
Transmission Electron Microscope Studies of Thin Films of CdSe Vacuum Evaporated from Knudsen-Type Source
A Knudsen-type evaporation source was used for the vacuum deposition of thin films of CdSe to study their growth and microstructure on to air-cleaved KCI and mica substrates under different rates of evaporation and substrate temperatures. The conditions for the growth of epitaxial films of this material onto mica have also been established and their photoconducting properties evaluated. CdSe films prepared by this source retain their stoichiometry and compare well with those prepared by other sources of vacuum evaporation
Preparation and Characterization of Nano-Dy 2
Composite polymer electrolyte films containing various concentrations of nano-Dy2O3 (1.0 to 4.0%) in PVA + sodium citrate (90 : 10) are synthesized adopting solution cast method and are characterized using FTIR, XRD, SEM, and DSC techniques. The investigations indicate that all components are homogenously dispersed. Films containing 3% of nano-Dy2O3 are more homogenous and less crystalline, and the same is supported by DSC studies indicating the friendly nature to ionic conductivity. Transference number studies reveal that the major charge carriers are ions. With the increase in % of nano-Dy2O3, the conductivity increases and reaches maximum in 3% film with a value of 1.06 × 10−4 S/cm (at 303 K). Further, the conductivity of the film increases with raise in temperature due to the hopping of interchain and intrachain ion movements and fall in microscopic viscosity at the matrix interface of the film. Electrochemical cells are fabricated using these films with the configuration “anode (Mg + MgSO4)/[PVA (90%) + Na3C6H5O7 (10%) + (1–4% nano-Dy2O3)]/cathode (I2 + C + electrolyte),” and various discharge characteristics are evaluated. With 3% nano-Dy2O3 film, the maximum discharge time of 118 hrs with open-circuit voltage of 2.68 V, power density of 0.91 W/kg, and energy density of 107.5 Wh/kg are observed. These findings reflect the successful adoption of the developed polymer electrolyte films in electrochemical cells
A Study On The Number Of Edges Of Some Families Of Graphs And Generalized Mersenne Numbers
The relationship between the Nandu sequence of the SM family of graphs and the generalized Mersenne numbers is demonstrated in this study. The sequences obtained from the peculiar number of edges of SM family of graphs are known as Nandu sequences. Nandu sequences are related to the two families of SM sum graphs and SM balancing graphs. The SM sum graphs are established from the inherent relationship between powers of 2 and natural numbers, whereas the SM balancing graphs are linked to the balanced ternary number system. In addition, some unusual prime numbers are discovered in this paper. These prime numbers best suit as an alternate for the Mersenne primes in the case of the public key cryptosystem
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