20.500.12556/RUL-173510 Priprava in testiranje vezja za balansirano merjenje Hallovega koeficienta kovinskih materialov Preparation and testing of a circuit for balanced measurement of Hall coefficient in metallic materials Meritve Hallovega koeficienta v kovinskih materialih so zahtevne, saj pri njih poleg majhega signala Hallove napetosti merimo še potencialno znatno večji napetostni prispevek, ki izvira iz upornosti vzorca in nesimetrične postavitve merilnih kontaktov. Ta neželjeni prispevek lahko močno poslabša ali celo onemogoči natančno določitev Hallovega koeficienta. Cilj zaključne naloge je bil razvoj in testiranje zunanjega elektronskega vezja, ki omogoča meritev Hallovega koeficienta z balansiranjem oziroma pettočkovno meritev Hallovega koeficienta. Osrednji del vezja je natančen delilnik napetosti, s katerim uporabnik pred začetkom meritve, pri ničelnem magnetnem polju, kompenzira oziroma "izbalansira" napetostni odmik. S tem postopkom se v zadostni meri izolira signal, ki je odvisen od magnetnega polja, kar omogoča zanesljivo določitev bolj točne vrednosti Hallove napetosti. Delovanje izdelanega vmesnika smo preizkusili z meritvami na referenčnem vzorcu bakra v sistemu za merjenje fizikalnih lastnosti PPMS. Rezultate, pridobljene z našim vezjem v kombinaciji z dvema merilnima opcijama (ACT, Resistivity option), smo primerjali z referenčnimi meritvami, opravljenimi z tovarniško vgrajeno opcijo za balansiranje. Pokazali smo, da vmesnik uspešno deluje in omogoča pettočkovno meritev na standardnih štiritočkovnih merilnikih upornosti. Čeprav meritve z razvitim vezjem kažejo nekoliko večji šum v primerjavi z referenčno metodo, vmesnik predstavlja delujočo in cenovno ugodno rešitev. Njegova uporabnost je še posebej pomembna, ker se namenske merilne opcije z vgrajenim balansiranjem ne proizvajajo več, s čimer naše vezje zagotavlja možnost izvajanja tovrstnih meritev tudi v prihodnosti. Measurements of the Hall coefficient in metallic materials are challenging because besides the small Hall voltage signal, one is measuring a potentially significantly larger voltage contribution originating from the resistance of the sample and the asymmetrical placement of the measurement contacts. This unwanted contribution can greatly impair or even prevent the accurate determination of the Hall coefficient. The aim of the final project was to develop and test an external electronic circuit that enables us to perform Hall coefficient with balancing or in other words a five-terminal Hall measurement. The central part of the circuit is a precise voltage divider, which the user uses to compensate or "balance" the voltage offset before starting the measurement, at zero magnetic field. This process sufficiently isolates the signal that depends on the magnetic field, enabling reliable determination of a more accurate Hall voltage value. We tested the operation of the manufactured adapter with measurements on a reference copper sample in the PPMS physical property measurement system. The results obtained with our circuit in combination with two measurement options (ACT, Resistivity option) were compared with reference measurements performed with the factory-installed balancing option. We have demonstrated that the interface works successfully and enables five-point measurement on standard four-point resistance meters. Although measurements with the developed circuit show slightly higher noise compared to the reference method, the interface represents a working and cost-effective solution. Its usefulness is particularly important because dedicated measurement options with built-in balancing are no longer manufactured, which means that our circuit ensures that such measurements can continue to be performed in the future. Hallova napetost Hallov koeficient meritev Hallovega koeficienta z balansiranjem pettočkovna meritev Hallovega koeficienta PPMS ACT ETO opcija za merjenje specifične upornosti Hall voltage Hall coefficient measurement of Hall coefficient with balancing five-terminal Hall measurement PPMS ACT ETO Resistivity option true false false Slovenski jezik Angleški jezik Zaključna naloga 2025-09-18 08:15:28 2025-09-18 08:15:32 2025-11-10 03:35:05 0000-00-00 00:00:00 2025 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 153905 250327043 19541.pdf 19541.pdf 1 87996DD7B9091549D06A233ECFD6FDA2 66ae790401f74a0bc673ae6863de3ff9f9db2307604de50a25ddfd242a7ae3ee b5e1f94b-9456-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=218025 Fakulteta za matematiko in fiziko 0 0 0