Samsung Electronics Co Ltd is closer to losing its crown as global smartphone leader after posting a plunge in quarterly mobile earnings on Thursday, a day after rival Apple Inc (AAPL.O) reported the biggest profit in corporate history. It was the mobile division’s fifth consecutive quarter of decline, in contrast to Apple’s record-breaking 74.5 million iPhone sales in the three months to Dec 27 on the back of the success of its big-screen iPhone 6 and 6 Plus.