676 research outputs found
Theoretical studies of spin-dependent electrical transport through carbon nanotbes
Spin-dependent coherent quantum transport through carbon nanotubes (CNT) is
studied theoretically within a tight-binding model and the Green's function
partitioning technique. End-contacted metal/nanotube/metal systems are modelled
and next studied in the magnetic context, i.e. either with ferromagnetic
electrodes or at external magnetic fields. The former case shows that quite a
substantial giant magnetoresistance (GMR) effect occurs () for
disorder-free CNTs. Anderson-disorder averaged GMR, in turn, is positive and
reduced down to several percent in the vicinity of the charge neutrality point.
At parallel magnetic fields, characteristic Aharonov-Bohm-type oscillations are
revealed with pronounced features due to a combined effect of:
length-to-perimeter ratio, unintentional electrode-induced doping, Zeeman
splitting, and energy-level broadening. In particular, a CNT is predicted to
lose its ability to serve as a magneto-electrical switch when its length and
perimeter become comparable. In case of perpendicular geometry, there are
conductance oscillations approaching asymptotically the upper theoretical limit
to the conductance, . Moreover in the ballistic transport regime,
initially the conductance increases only slightly with the magnetic field or
remains nearly constant because spin up- and spin down-contributions to the
total magnetoresistance partially compensate each other.Comment: 15 pages, 6 figures (to apppear in Semicond. Sci. Technol.
The Croatian Health Survey ā Patient\u27s Satisfaction with Medical Service in Primary Health Care in Croatia
The aim of the study was to investigate patient satisfaction with nurses and general
practice organization in Croatia. A total of 2,252 patients 18 years of age and over from
47 randomly selected general practices were included in the study. 72.1% of patients
were satisfied with nurses and general practice organization. Older and less educated
patients were generally more satisfied. Patients were more pleased with nursesā behavior
(81.9%) than with practice organization (62.3%). Factor analysis revealed two underlying
discriminates of patient satisfaction ā Ā»positive attitude towards the nurseĀ«
and Ā»inaccessibility of practiceĀ«. The former discriminate emphasized a great potential
of nursing, which should be taken into consideration in the transformation of health
care system in Croatia
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